Sleep Science vs. Zinus

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Do NOT buy. The worst!
The worst business and absolutely appalling customer service. Liars. Purchased a mattress and decided to cancel order within 48 hrs due to the recent law suit. I spent 2 days emailing and calling without any results and then got an email that the mattress was shipped. I was furious. I then began to contact about the return and refund. Again, the same story, every CS rep I talked to, lied to me saying I'll receive a shipping label within 24-48 hrs, 10 days later, still nothing. The mattress is sitting unopened in my garage. I've filed a dispute with my CC and hopefully will get some money back. This is theft of my $500.

Mold on the bottom of mattress
I purchased this bed 9 months ago and just turned it over to find mold all over the bottom of the mattress. It could only have come from the mattress because there isn't any mold anywhere else in my entire home. The company refuses to do anything about it saying it could be from an outside source. But how could the mold only be on the mattress and not even the box spring or anything else? I don't know how long there has been mold but there is a good amount so obviously a while. This has been making me sick and my allergies horrible. Last night was the first night without the mattress and I didn't wake up with a headache, my nose wasn't stopped up, and my throat didn't hurt. I feel disgusted that I have been sleeping on mold and that the company didn't care at all. I wish I never bought this mattress. These pictures show the mold with and without the mattress protector.

its like sleeping on the bottom of a crater
well i read so many reviews calling this mattress firm,i will tell you this,an 8 inch mattress goes to about 1 inch soon as you lay down on it,its like sleeping on the bottom of a crater,you feel like you need a step ladder to get out of bed,i am 6ft,200lbs,average build,it just engulfs me ,its like dropping a marble on a cotton ball,the marble has no support so drops til it reaches a bottom,my biggest fear now is when it engulfs me i will disappear from sight,help i been swallowed by my bed and i cant get out!!!

These are great mattress! This is the second one I purchased
These are great mattress! This is the second one I purchased. I originally had a full size and then upgraded to a king size recently. I used the first mattress for two years at least and I am 140lbs and have no complaint, the mattress is still good and will be used in my guest room. The new king size is doing just fine.

Sleep Master, Indeed!
Wow! I am impressed with this bed!
My husband and I have had a memory foam mattress that we purchased eight years ago from Sam's Club, and we have liked it, but we wanted to move from queen to king size. We shopped everywhere online trying to find the best bed for the lowest price. This is it.

Here are the things we experienced:
--NO smell at all. I am sensitive to smells and have asthma. Neither my husband nor I smelled anything. I put my face in the mattress right after opening. Nothing. Certipur is one feature I required, and I say it is valuable.
--Was expanded to 12 inches in less than an hour after unpacking. (Indoor air temp. about 75F. Outdoor about 87F that day.)
--Soft top half, feels like a pillow topper but with support underneath.
--Warm and cozy -- we will save on heating in the winter.
--NO stiffness in our bodies, noticeably no pain in the morning. This shocked us; we thought all memory foam would do that and that any soreness we had was just us getting older. Nope. This bed made a difference in our bodies.

My husband likes firm; I require soft. I am pear shaped and a back and side sleeper, and a firm mattress arches my back and hurts my tailbone, hips, and lower back. I have to have something that lets my booty/hips sink. My husband has scoliosis and lots of back pain and needs support. He is also a belly sleeper and needs support for that as well. We are both VERY happy with our sleep experience! I don't know how this is possible, but I guess it's the "Sleep Master" experience and the beauty of memory foam.

It arrived on time, in a box about four feet tall and wrapped in two layers of compression materials.
Here is our setup after removing the cardboard box:
We set up the box springs (two Twin XL) and frame. My husband handled the mattress by himself, unboxing it, pushing the rolled mattress down the hall, lifting it onto the box springs.
The instructions were simple and clear. We removed the first layer of packaging (which was a white plastic tarp-like material with reinforcement), positioned the mattress (still compressed in a second layer of clear plastic) in the center of the box springs and realized it was folded in half with the wrong side up. At that point, my husband and I had to lift the folded half to position it correctly with the zipper side down, and this was the most awkward part. Once in place, we removed the second layer of compression material. Magic! It started decompressing and was a full 12 inches in less than an hour.

I can recommend this mattress with confidence. We're happy, more-than-satisfied, and well-rested.
Sweet dreams!

and they mostly get very good reviews. This model
I chose this particular model for several reasons. First, it is manufactured by Zinus. Now, Zinus does not have the name recognition of Tempur-Pedic, nor the same high-end reputation, or prices. Various Amazon sellers sell at on of assorted Zinus mattresses under a bunch of names, and they mostly get very good reviews. This model, a 10" Queen featuring 3 inches of memorey foam over "2 inches Pressure Relieving Comfort Foam," on top of 5 inches of higher-density base foam, appears to be identical to other brands that receive 4+ star ratings over numerous sales here. Add to this the fact that this particular listing was both shipped by and sold by Amazon, and I felt I couldn't go wrong. And, of course, my innerspring mattress was 15 years old and needed to replaced.
I received the mattress only today, and have only slept on it for a few hours, and will update this after a few weeks and maybe later. Prime 2-day shipping didn't fail me, and the 65 lb box was dropped right next to my house by FedEx. I handled the box fine myself but it was a little bigger than expected and without any handles, and a lot of people will definitely need help to move it up any stairs, if not move it all. Neatly packed, nothing extra, no cushioning needed.

Some reviews of memory foam mattresses led me to believe they can take 24-48 hours to fully expand from their compressed shipping state. Others caution you to have the mattress at least near where you will ultimately sleep on it before you unwrap it. The second bit of advice is defintiely worth mentioning; mine expanded and unfolded rapidly, reaching near-full dimensions in seconds. After wrestling it of the floor (I should have opened the plastic with it on the platform), I measured its height at 9 inches. Two hours later I found it a full 10 inches high. It is also a full 60 x 80, unlike many mattresses on Amazon that are undersized at 58 x 78 inches. That is a big deal to me - I want all of the 80 inch length a proper queen mattress provides, and filling out standard sheets without them being loose or baggy is a must.

I have not had a full night's sleep as of this review, but I did take a quick nap, which turned into a very long nap. It is comfortable. This mattress cradles me enough, yet is still firm enough to be supportive. Time will tell, but my initial impressions of this mattress are that it will be great to sleep on, and that it is a real bargain.

I have a problem with this mattress....
It is so darn comfortable that I don't want to get out of bed!! I seriously have no idea why I spent $1200 on my previous pillow top that was not even that comfortable to begin with when I could have been sleeping on memory foam this whole time.

There was no chemical smell at all that I could smell. Within 2 hours it was puffed up to full height and ready to go. I was expecting a mattress that was really firm from some of the reviews on here but it really isn't. It is soft and as soon as you lie down the foam melts around your body. I don't think I have had this quality of sleep in a long time. I am a toss and turn kind of person but not on this bed.

For the price you absolutely cannot beat it. I would recommend this bed to anyone, especially people who sleep on their sides. That is how I sleep and usually in the morning I wake up and my hips are in so much pain, but no more!

Just as a testament to how comfy this bed is...my son decided to climb into my bed in the middle of the night the first night I bought it because he wanted to sleep on the new bed. Usually he is up at 5:30. He slept in until 7:30 and even then I had to wake him up! I think I am going to buy one for his bed as well!

Awesome mattress not the cheap oem that comes with the rv.
Great mattress, true 10" and no smell as other reviews claim to have... Medium firm awesome I let it breath for 8 hrs and perfect, it was ready to go within 2 hrs.
Buy with confidence you won't regret it.
Capt. Jay

It's comfortable enough for a good night's sleep
My fiance and I have been using this mattress for a year now with no troubles. For reference, I weigh 130lbs and he weighs 330lbs, so you'd expect some sagging on his side, but we haven't noticed any yet. It's comfortable enough for a good night's sleep, although if I have a cat sitting on me, the uneven weight makes my hips dig into the mattress. For the price, this is as good as it's going to get. Highly recommend if you're looking for an inexpensive bed.

Best mattress ever!!!!
The most comfortable mattress I have ever laid on!!!! Buy it - do not hesitate. Worth every penny and more!!! Small chemical odor but I assume that will go away with time. Super thick. Medium firm.

Very Good Mattress at an Excellent price.
This is a VERY NICE mattress and a wonderful addition to our guest room. It arrived as promised when the mail carrier drug it across our driveway and left it about 25' from the truck. The box was "solid" and felt much heavier than the 48 pounds the scales said. We used a hand truck to carry in into the bedroom. Having seen the warnings, I carefully opened the ends only to find what looked like a stuffed laundry bag. At first I tried to slip the bag off it but there was too much tension. So I took scissors and carefully slid them between the plastic mattress cover and the cloth bag. As I did it literally popped open on the box springs wrapped in a heavy plastic cover. After taking that off we opened it for the two day "airing out" period that was recommended. There was a mild odor at first that was gone by the second day.

The white cover was opaque so I couldn't tell for sure which side was the top (hint: the zipper goes down). We bought it for the guest room, but slept on it the first night. We didn't want something in there that we wouldn't like. It was EXTREMELY comfortable, and much more comfortable than mattresses costing double or triple the price that we tried. It is not a soft mattress, yet not too firm, but has a comfort that gave us a good night's sleep. The only difference either of us could tell with or without the bed board was that the sides didn't sink down as much with it -- so we left the bed board under the mattress. I suspect it would be almost as comfortable just placed on a floor without any springs.

One VERY MINOR "problem:" It is slightly larger than the box springs. As advertised, after it opened, it was 75x54x8. Full size box springs are 74x53. The 2" extra width is not a major problem and, as shown, is hardly noticeable. It does somewhat affect how much the side squishes down when you sit on the edge of the bed. The bed we put it on has both a headboard and foot board so the 1' extra length is not even noticeable.

I'm glad we purchased this mattress. It is a welcome addition and upgrade to the very old set we just removed from the bed and something our guests are sure to enjoy.

I never want to get out of bed now...
*** I did NOT receive this product in exchange for my review. I am not cool enough for that. ***

I ordered this mattress for my son, who specifically wanted a "mattress I sink into" to replace his aging Sealy "twin mattress that you give to your 8 year old because it was on the bottom trundle of someone's daybed for a decade and was slept on maybe twice but it's from a time when mattresses were FIRM like John Wayne's resolve!"

I did a ton of research. This product has nearly identical branding to three other mattresses on Amazon - identical documentation, identical "composition diagrams", everything. But it's $50 more. Why the price discrepancy? Because apparently Zinus is a real company that actually honors warranties. At least that's what I hear.

As everyone else indicates, this shows up in a duffel bag. The instructions are flat out wrong - it shows up folded in half and upside-down before being rolled up. You have to unroll it, unfold it, THEN flip it over, THEN cut the bag off. The only good news is that since I only bought the "full" it wasn't all that heavy. Then again, I'm a big guy. If you are a teenager or slender woman I would imagine this is not something you'd want to move all by yourself.

Once it's unfolded and inflated (which took about 24 hours to reach full firmness and regain its shape) it is a mattress sized (and shaped) chunk of memory foam so moving it around is unwieldy, but no more so than an actual mattress.

It is EXACTLY full-sized. And it is PERFECTLY rectangular. Just like the picture. It fits snugly (but not so snugly that we couldn't get a mattress pad and sheets on it) into the full-sized platform bed from IKEA that my son sleeps on.

When first inflated (for the first 24 hours) sitting up on the edge of the bed resulted in instantly crushing the entire mattress. The first time I climbed onto it, my knee touched bottom. That all changed within the next 24 hours. It is now firm, and even with my son sitting on me my hips don't bottom out. I'm sure I'm touching the support foam, but that's it. Sitting up in bed now results in a good amount of mattress supporting my butt. And I'm not light.

The included cover is decent - and zippered for removal so washing will be easy.

Now, the good part.

It's memory foam. In a 10" mattress. I took the zipper off and it indeed looks as intended - several inches of memory foam (hard to say if there's really a "comfort foam layer" or if it's just more of the same memory foam, as it's the same color) and several more of support foam.

It's REALLY comfy. As in "lie down and you don't have to toss and turn or adjust yourself or even really use a pillow because OMG it's comfy" comfy.

It retains its shape, it doesn't seem overly hot (it is supposed to be a cooler type of foam, after all) and it seems to be exactly as promised.

I will update this if that ever changes. And I might just have to buy one for my own bed, I'll be doing a sleep test this weekend!

One even said it's like sleeping on a marshmallow
All my roommates sat on this, and they each want one now. One even said it's like sleeping on a marshmallow. It came very nicely packaged. I had no problem opening it and airing it out for about 30 minutes. Description said it may have a natural foam odor, but I didn't even notice. Had it half a year and I've been able to sleep easier and longer.

Foam is not just for beer anymore!
Like many folks here, I bought this for my son (9 yo). Came vacuum packed, which is cool. My wife unpacked it and I carried it upstairs (she could've but that's how I roll). Real comfortable, especially for a kid. At 225 (think lean muscle and smoldering good looks) when I sit on the bed my butt does bottom out on the boxspring a bit, but once you distribute your weight you are going to feel like Han Solo frozen in carbonite (except you will be smiling).

Memory Foam Take Me Away
I've been sleeping like a baby since switching to this mattress. Very pleased. It took approximately an hour for mattress to fully expand; left it on top of the pool table for a few days prior to moving it to the bed. Purchased the full size. Love that you cannot feel your spouse moving during the night. Will eventually change all of the mattresses in the house to this Ultima memory foam.

Great value for a standard size mattress, exceptional value for a short queen.
It's a bit taller than I expected (don't know why, it's as thick as the description states). Fits the space in our 5th wheel perfectly, much better than the crappy standard queen size bed the previous owners included. Just the right amount of tossing and turning at night (this is more important than you think, if the bed is so comfortable you don't move at all during the night you'll hurt quite a bit in the morning...this explains many "felt great the first couple weeks but then I got really bad back pain and had to throw it out" reviews that some mattresses get).

It's honestly one of the most comfortable mattresses we've had. Easily worth twice the price (though I wouldn't have paid that much). And the short queen wasn't much more than a regular queen, which made it an even better buy (short queen mattresses, common in RVs, generally cost much more than the larger standard queen, and quality often leaves much to be desired).

I was hesitant because some said its not good for daily use
Please know I'm a Tempurpedic lover - I had the Cloud and also the Grand Bed. I bought this to sleep on every night because it's all that fits in a tiny room. I was hesitant because some said its not good for daily use, others said it smelled, some said it was cheap. I've slept on it 4 nights now and it's AWESOME. There was no smell at all (even when I opened it), I DID wait 24 hours for it to fully puff up before sleeping on it. I sleep on my side and I swear it's more comfortable than my old Tempurpedic. Laying on my back to watch tv is fine too. I wouldn't call it firm or too soft, the memory foam is just right for me and I have had NO back pain. I'm a skeptic so I am shocked at how great this really is. Give it a shot and buy it!!

Sleep Master 8 inch purchased 1 year ago
First I must say I thought they made a mistake when I received the mattress. It was delivered in a box, well not use to seeing a mattress all fold up in a box. Once I opened it and placed it on the bed again I thought they made a mistake. I got a tape and measured the width it was not 8 inches as ordered. Well it just took some time to open up to it's correct size. After a year I have no issues with the mattress and if you are use to the spring mattresses you can feel the difference with this sleep master. I am thinking of getting another mattress and it will most likely be the same one.

Terrible mattress...Replaced after a year
This mattress went from the best mattress we ever bought to the worst, most uncomfortable mattress we'd ever slept on in under a year. At first we raved about this mattress and recommended it to a few family members and friends. Thank god they bought different brands because this has turned out to be one of the worst investments we ever made. Last year the mattress was about $75 more expensive and we didn't have a huge budget so we got what we could afford at the time. But maybe 7 months later we started finding it uncomfortable and here we are 1 year and 3 months later and we have just purchased a new mattress to replace it.

Basically it just doesn't hold up. It has absolutely no support. It is lumpy and painful. We feel the bed frame or box spring (we tried it with both) underneath when we sit down. At night when I roll over I feel my hips hit the box spring below at this point. Both my husband and I are miserable on it and have had back aches for the past few weeks.

Do not waste your money.

Awesome mattress for those on a budget!
I was definitely leery about buying a mattress online. I went to Sam's Club, Mattress Warehouse, Bedding Barn, yadda yadda, and tried a million different mattresses. All of them were lovely, but none of them were cheap. Is this bed stellar? I wouldn't call it that. But it is a wonderful bed for someone who really doesn't want to spend much more than 200$ on a mattress, and someone who certainly doesn't want to try to haul a huge ass mattress on the top of her little Ford Fiesta.

PROS -

1. Cheap.

2. Cheap.

3. Cheap. Seriously, where the hell else are you gonna get a decent mattress for this price?

4. It comes to your house in a box. You open the box, open a bunch of bags, and the mattress gloriously unfolds for you. After having moved sofas and tables and desks and lamps into my apartment, it was MAGICAL to have something normally so bulky arrive and take pretty much zero work to set up.

5. It's a good mattress. I've had it for almost a month now, I sleep well, there's no noticeable comfort issues. Many of the negative reviews I read mentioned that it was too firm, firmer than they were expecting. I think that's because when people think memory foam, they think Temperpedic. See the con section below for more on that, but given all of the complaints about the firmness I was pleasantly surprised with the softness of it. It's firmer than I like, but it does kind of contour to your body. Also, unlike Temperpedic, this mattress doesn't trap all of your body heat! I hate waking up sweaty so this was a huge plus.

CONS -

1. Smallest con ever: it smells funny for like, 10 minutes after you get it. Really not a big deal though.

2. Do not expect this mattress to be a Temperpedic. If you've done any research on mattresses, you'll know that cheaper memory foam mattresses use a cheaper, different density foam than the fancy ass Temperpedics. (If you haven't done research yet, I suggest the Sleep Like the Dead website.) The skinny on these mattresses is that they run firm. And yes, this bed is firmer than I prefer. But see the PRO section above for why this doesn't matter to me that much.

3. Now I don't know this first hand, but I have heard that there's really not much you can expect in the way of customer service from this company. And honestly, if you order a bed-in-a-box like this, open it and find out 2 weeks later you really don't like it, what are you going to do? You can't ship it back, because there's no way you can squeeze the mattress back into the box. So I'd suggest trying out a bunch of mattresses, making sure that you're okay with something like this, I would say softer than a firm pillowtop, but firmer than a high density memory foam mattress like Temperpedic. Be REALLY sure you want to buy this before you place an order.

ALL IN ALL - This is a good, budget mattress. Generally speaking with mattresses you get what you pay for, but I would say this is a really good deal.

Has made a world of difference for my overall sleep and body
Perhaps this review will help you.....

Details: I am 5'10", 268 pounds, stocky, and was recently not-exactly-diagnosed with sleep apnea. My doctor believes I may have this issue, but without tests, hard to confirm. I had bought a Serta Plush Firm mattress that basically just got flat on top and was left with firm.

So, my review of this mattress is based upon the following:

1) Ease of assembly/setting up: The box they put this in was not exactly super heavy but was awkward to move around. Once I got it out of the box and on the frame it was super simple to set up. Remember: The zippered side goes on the bottom!

2) Inflating: I received the mattress around 2:15 in the afternoon and had on the frame by 2:40 (note: That is only 25 minutes). It was fully inflated in just a few hours and I slept on it that night. If you get the mattress and it arrives after 7PM, let it inflate and sleep on it the next night.

3) Smell: Unlike others I did not have any type of overpowering smell. It just smelled "new." TIP: If you think you may be bothered by the new smell, run your sheets through the washer and use some Snuggle concentrated fabric softener. It's got a great smell and will counteract any "new" smell of the mattress.

4) Firmness: When you first crawl onto the bed it feels a little firm, but then you sink into it and it really does conform to your body. I always lay on my back and watch some TV when I first get into bed at night. The first night I turned the TV off and laid to my left side. I felt the mattress firming back up to conform to my body.

5) Adjusting: With my old mattress I had to toss and turn several times before I finally got to sleep. I ordered this mattress on Halloween and it arrived 2 days later thanks to Prime. Every night since (over three weeks now) I got this mattress I roll over after turning the TV off and I am asleep within 5 minutes! I have not had to toss and turn any night since to get comfortable and fall asleep.

6) Other: With my old mattress during the day I was constantly having to turn my body to try and "pop" the bones around my lumbar area. I'm not doing any of that any more. Also, I would wake up previously and have to stretch my legs and they would just pop from no getting good support. They are not doing that any longer, either.

7) One person said you may not need a pillow and I think another said you will not need two pillows. I am not so sure about the no-pillow option but two will definitely not be needed. I bought a memory foam pillow a few months ago at Belk. It was an Isotonic something or other, and it has relieved all of my neck pain. It was the precursor to getting a memory foam mattress.

8) Heat: I have not had one problem with heat, and I am hot natured. I have bamboo/rayon sheets and they are very breathable and soft. I have an alternative-down memory foam comforter on top of that. I keep my house around 65 year round.

9) Overall: I would recommend this mattress to anyone who asked, and I would purchase again if I had to do all over again.

I hope this helps. Any questions? Feel free to comment and I'll be happy to answer!

10/18/2014 UPDATE: Almost one year later and I am still loving this mattress! The side I sleep on has held it's shape greatly. I am thinking about turning it around on Halloween (1-year- anniversary) to see how the other side compares since I have slept on the same side a whole year. As of today (10/18) the mattress is on sale for almost $100 off! You can't go wrong with this mattress. Also, about the heat: I dropped the bamboo sheets as they were crap! Going back to regular cotton sheets was a tad warmer, so just lower your A/C at night and you'll be fine!

Read this
I am a chiropractor for 30 years. This is the best bed of all time and the best price on the internet. The bed completely conforms to your neck and body. You don't even need a pillow. I would do a commercial endorsement for free.

Wary at first, but a great deal
I went back and forth on buying this. I was raised with the "you get what you pay for" and "if something is too good to be true, it probably is" mentality. So when I saw this, for the price here, I was skeptical. The reviews were overwhelmingly good, but with my bad back, I was really wary about buying a bed without testing it out, buying a mattress for less than $300, and very concerned about how I was going to make do if it didn't work out. But, being on a budget, the choice became this or a donated futon mat... It didn't take long to make the choice after that.

The bed arrived in a box about 18" x 48" x 18". Looked a little bit like a cardboard coffin, actually. It came upstairs with little fuss (it was heavy, but not too bad), and we opened it up. The packaging was secure, and thick enough that I wasn't worried about cutting into the mattress. YOU DO HAVE TO BE CAREFUL IF YOU USE SCISSORS. There is a little room within the box, but not much.

We don't have a box spring yet, so the mattress went onto the floor directly. Within minutes, it was fully puffed up, and so comfortable, I couldn't believe it. We added a thin bedspread to it for extra padding over the sheet, and that did the trick to balance out the lack of bed frame or box spring. The smell that people talk about was gone by the time the bed was done expanding, but I would recommend you open a window or leave the door open, or even turn on a fan, while it's doing its thing. If I'd left the room closed up, the smell could have been overwhelming.

So, the rundown:
* Great price
* Easy to set up
* Works with bad back
* Cushy, but not overly so
* Not too firm, just about right
* Even comfortable on the floor
* Smell, but not overwhelming and gone quickly

Love this mattress!
I was skeptical about this bed, so cheap. Let me tell you I have not slept better than this in the past 10 years. I work 2 jobs, and have chronic back pain (bulging disks). I wish I would have found this bed years ago.

Will buy another!!!!!
Excellent mattress! I've had a tempurpedic for 10 years and it was time for a new mattress. I've had 10 spine surgeries and 7 spinal fusions and this mattress is amazing. No pressure points and you don't over heat like the older tempurpedics. A great deal!!!! Couldn't be happier

Size is not correct
This product is not the same as a full size bed, It is much smaller. I have no Idea how to send this thing back?
Looks like it would be comfy but does me no good the way it is...

Fantastic mattress!
This is probably the most comfortable mattress that I've slept on. On our old mattress, I would go to sleep at 9:30pm and wake up at 5:45am. I figured this was a good schedule to me. After getting this new mattress, I've gone to sleep at 9:30pm but have woken up at 4:30am, having not moved at all. After that I toss and turn for another hour until it is time to get up because I'm already fully rested and don't need to sleep anymore.

For me, this mattress is not too firm nor too soft. For some, it may be too firm, as this "memory foam" is not the same stuff as the higher end brands. That is neither praise nor critique. Whatever the foam is (3 different layers of different foam), I'm loving it.

I searched for a while and could find no videos on this mattress so I posted one on youtube. You can find it by searching "Sleep Master 12-Inch Pressure Relief Memory Foam Mattress" and look for the video with the thumbnail reading "Sleep Master Mattress Unboxing".

Comfort and nothing but. UPDATE 4 yrs after
It's been a long time and this mattress remains in the same condition as when I bought it. It hasn't lost any of the characteristics I've been loving throughout these years.
I've been sleeping on it on a daily basis with not a single minute of regretting.
6' tall, 260lbs, and sleeping really well, I have not experienced temperature problems, loss of firmness, deformation, or any other so far, so I thought it would maybe be of help to others to do this update.
My original review (below) stands after all this time, and I still recommend this product.

I find this to be a great product.
As my bones have grown older and my joints crankier I've tried several different mattresses, some better than others, some pricier than others, but for the first time I can say this is simply the best one I've slept on so far.
It is soft enough while firm enough as to provide great comfort to a person like me, with joint-related issues. I can sleep all night without having to wake up to move for a while and without more tossing and turning. I wake up in the morning fully rested, with no pain or discomfort whatsoever.
In my case, I did not experience the problem of strong chemical odor other reviewers have referred to, the mattress expanded really fast and evenly, and after a fairly long trial period I am completely satisfied with the product.
I will not say it may be the best mattress out there, but it is the best of the many I've tried, and the price is excellent.
I will keep it.
Great product. Highly recommended.

Look no further, this is your mattress!
I will start by saying that it is VERY rare that I would take time out of my schedule (even 15 minutes) to write a review. This mattress however deserves a positive review of more than 5 stars if that were an option. I currently own one of the original foam Tempurpedic mattresses. It is 10 years old and still in great condition. My situation is that I have recently had a major back surgery. A fusion from L4 L5 S1. With being off from work during my recovery, I have taken on a temporary roommate to assist with bills and mortgage. I moved from my master bedroom to my spare bedroom to accommodate my roommate whom I need more than she needs me. Anyway, the smaller bedroom would not accommodate my queen size bedroom set so I chose to put a twin size bed in my room. I then had to find a preferably foam mattress for a twin bed. I read many reviews on foam mattresses and compared pricing on multiple sites. Trust that I have done this research for you and you need not look any further! I am a flight attendant and I can say that I have slept on hundreds of beds across the United States and beyond. This mattress is amazing and comparable to my queen size Foam Tempurpedic that cost a couple thousand dollars! I am still healing from my fusion surgery and I am so impressed with this bed's ability to conform to my body. As a curvy women, the bed gives where it needs to. I don't feel as though I sink down into it. It is soft yet supportive. I have invited friends and coworkers to sit and lay down on this bed and they have all been very impressed also! A couple have already stated that they will purchase this mattress themselves. When I require a new foam mattress or if I decide to upgrade to a king size bedroom set, this will be my mattress of choice! Do not waste your time or money on any other mattress besides this one!

Looking forward to restful nights again.
I bought this mattress to replace my 12+ year old memory foam that was 8 inches in depth and has served us very well. It too was an online purchase in an effort to have the comfort of a memory foam and not the expense of a Temper Pedic. We just took off the old mattress, unwrapped the new mattress and put it on our bed. Within 5 minutes the thing had already expanded to it's full 12 inch height and completely filled our California King bed frame. I took the liberty of falling down on it just for a dry run through since I know we need to let it set for approx 24 to 48 hours for it's full expansion. Gosh, it was like falling into a cloud. My husband and I are in that middle age spread thing with plenty of arthritic joints to go around and this mattress should fit the bill of supporting all those achy spots the old mattress had stopped supporting.
I read other reviews that mentioned the bed was hard, but ours couldn't be softer. Another mentioned that they repeatedly got defective, lumpy mattresses, ours was perfect first time out of the box. It is in fact, softer than our previous memory foam and there was little or no odor coming out of the plastic wrap. I am genuinely tickled pink with this purchase and look forward to sleeping like the dead on it. What an awesome buy for the money and can't recommend it enough!

Quiet but can be quite hot.
Great bed. Very quiet. No issues with springs or creaky wood box spring. Only critism would be that the foam holds heat. I purchased mine when it was still warm and I have been waking up sometimes in the middle of the night sweating. Hopefully it will be the opposite in the winter time.

Decreased Quality after 1 Month
I bought this mattress for my apartment in the beginning of January based on the overall good reviews. One month later I regret it.

The good:

Shipping & Delivery -
The mattress came in just over a week (without prime shipping) and was packaged in a box that I was able to easily take from the storage area of my apartment up the elevator and through the doors that led up to my room. I was also able to quickly and easily unpack the mattress and let it air out to its complete 8" size.

Mattress Quality (first 2-3 weeks) -
For the first 2-3 weeks of owning this bed it was great! My sleep quality considerably improved from my old mattress and the memory foam retained its shape and supported my body throughout the night.

The bad:

Mattress Quality (1 month in to present) -
Around the 1 month mark I started to have back pain and began to pay attention to how the bed felt as I got into it each night and what it looked like once I woke up in the morning. The mattress had begun to lose a lot of its shape and the memory foam was supporting my body less. Instead, I was just sinking into the mattress and it was no longer providing the support I needed.

Overall you get what you pay for - a bargain price for a cheap memory foam mattress.

Comfortable if you like memory foam mattresses
This 8 inch memory foam mattress is working well on a foldable frame, without a box spring. I like memory foam, and I found it comfortable. It does "dent" for a while after using it, but does return to original size within a few minutes. True to size, sheets fit well. Would buy this again if the need arises.

Nice Mattress/Good Price
Bought three Twin Sleep Master 8" Memory Foam Mattresses. They arrived on time and after letting them expand for a couple hours they were ready to use. They don't have any worse odor then any other foam mattresses we've had and it goes away after awhile. They're pretty firm and perfect for my kid's bunk beds. The kids are satisfied and that makes me satisfied!

great buy ..i recommend this
better than I expected ..great buy for the price bed is comfy not too hard not to soft just right

This is the ultimate deal
This bed is soooo amazing!! I was skeptical about buying a bed online especially after reading a lot of mixed reviews but I was pleasantly surprised. This is the best purchase I have ever made. The mattress is soft yet also firm and it conforms to your body. It did not have a smell and expanded fully after a few hours. It's like sleeping on a cloud and it does not get hot. It is actually pretty cool, I would have to confirm in the summer time though. I also bought two 8 inch twin beds and my kids love it. I just hope that it lasts at least 5 to 8 years. If it does it is definitely worth the money versus buying those expensive mattresses in the stores.

Working well for a antique 3/4 bed!
We let the mattress expand on the bed frame (right on the wooden slats) and it filled in.....even though the size of the bed is different than a full size it didn't matter! It is extremely comfortable! I'm so happy that I didn't spend the money on a 3/4 mattress.

Two different experiences
First off, I bought this product in the twin size a month ago for a spare bedroom loft. I was pleased with the product. It is delivered compressed, and when it was unpacked, it sprung to life very quickly and evenly. Because I was pleased with it, I ordered a queen for the same spare bedroom. This was a completely different experience. After unpacking it, I was surprised how uneven it appeared, but since it had been compressed and I knew the instructions said to wait 48 hours, I didn't worry about it. Now 48 hours later, this is a mess. There are parts that are very nice, but there are edges that haven't risen back up, and sections of the mattress that are inches lower the the higher points. If you would run your hand down it, it would be a lump after the other.

I would not recommend this because of the second experience.

This is now the best feature of our camper trailer!
Now that's an AWESOME bed! We've been building up our camper trailer for a year now and finally got to install the bed. This last weekend we got to try it out and see about any changes needing made. The mattress is sitting right on the board over the bed frame. I was really cool unpacking it and seeing it "inflate", we let it set in the trailer for 2 days, as I cleaned out all of my tools, and scrubbed the trailer to get lived in for a weekend. My bride kept saying "You're gonna love this" but I was dirty from all the work and didn't want to try it out and mess it up.
In our house, we have a king sized pillow top that is pretty good, but I have been still waking up stiff. After two nights on this one, I'm simply amazed that I'm waking up rested again. I have knee, back, and neck injuries from my military service, so living with pain is normal. The wife may have to order a king sized just to keep me sleeping in the house!
BTW, we have the 8 inch thick mattress and it's actually more like 10 inches. I'm 180lbs and I can feel myself sink into this one a couple of inches. Not one pressure point. Don't even consider the thinner ones, the 8 inch is it!