I purchased the 8" Spa Sensations king-size foam mattress in late December 2011, so have slept on it a little over 2 weeks. This is my first foam mattress and the first mattress of any kind I've bought online. I had the same apprehensions about buying it that most others have:
· You cannot "try before you buy", even though sleeplikethedead.com's research shows that people who do that are no more satisfied than people who buy online.
· Given the 4-figure prices of king-size mattresses in brick-and-mortar stores, $245 suggests a low-quality product.
· The difficulty of returning a fully-expanded king-size mattress, should I not like it.
However, I was persuaded to go ahead by the overwhelming number of positive reviews on Walmart's site.
Walmart service: They were absolutely great about keeping me informed of the order status (when it shipped and when I could expect delivery). I was amazed at the short delivery time – just 4 days from order to delivery, and that was the week before Christmas!
The mattress: It's made by Zinus (www.zinus.com). Their instructions for unpacking and decompressing the mattress are sparse, but the process is not difficult to figure out without instructions. One thing they do not do, and should, is print "Top" on the cloth cover around the mattress so you immediately know which is the memory foam side (which has to be on top). Be sure to check by pressing the side that's on top BEFORE it fully expands. Having to turn over a 70+lb. fully expanded king-size mattress is not fun.
The instructions note that "it might take up to 48 hours for the bed to fully recover". As others have pointed out, the mattress contains solvent residue that is quite noticeable when you first open the bag. During the 48-hour decompression time, we put a fan in the room to help disperse the solvent and slept in another room for 2 days. But for about the first week, I could still occasionally detect a slight smell that gets trapped between the mattress and the bed covers, but the odor is not detectable at all in the room. Everybody's reaction to solvent odors is, of course, different, but I never found it objectionable – not even when the mattress had just been unpacked.
After sleeping on it for 3 days, I was not a happy camper. I like a relatively firm mattress, which the Zinus website says this is, but as a few others have complained, it seemed WAY too soft. I was getting ready to return it to the local Walmart store when I stumbled on a review of a competitor's foam mattress in which the reviewer said that the warranty would be voided if it had not been supported on a RIGID platform. I had put the mattress on the box springs that had supported our old innerspring mattress. They seemed relatively firm, so I thought they would be OK to use. WRONG! After reading the review, I immediately bought a ½" plywood sheet, cut it to size, reinforced the area where my torso lies by doubling the thickness (to prevent contouring), and placed it between the box spring and mattress on my side of the bed to see if a "rigid platform" made any difference. OMG! The mattress's behavior was TOTALLY different – FAR firmer (exactly the amount of firmness I wanted) and no "sinking" in the middle. In an instant, the plywood had transformed it from a mattress I didn't like to THE BEST I'VE EVER SLEPT ON. Incidentally, I'm trying the plywood-on-box-spring approach because it's inexpensive ($30 vs. >$200 for a complete platform). If the plywood eventually bows, I will buy a platform. Regardless, here's the critical point: A FOAM MATTRESS MUST(!) BE SUPPORTED ON A RIGID PLATFORM. If you use a foundation that "gives" AT ALL in the center, the mattress will seem way too soft/will leave you sleeping in a "trough". It's probable that at least some of the reviewers on this site who complained that the mattress is too soft did exactly that – put it on their old box springs.
Note to Amazon and Zinus: Neither of your companies mentions this as CRITICAL to making a foam mattress work properly. I strongly suggest you put it in the item descriptions and EMPHASIZE it.
Warranty: Although it's a tad difficult to find, and no papers come with the mattress mentioning the warranty, it's 5-years, unprorated. Most other manufacturers provide 20-year warranties, although virtually all are prorated after the first 2-4 years. If you would feel more comfortable having a 20-year warranty for about the same price as the Zinus mattresses, try Amazon.com's Lucid brand, which, because they employ only high-density foam topped with 2" memory foam, are likely to be somewhat firmer than the Zinus mattresses, which use 2" of "comfort foam" between the memory and high density foams. But keep in mind that if you don't like it, you will incur a sizable return shipping expense. Unlike Walmart, Amazon has no brick-and-mortar stores to return it to.