Let me begin by saying we really like the mattress. We put them directly on a Zinus 14' platform base and it's working well.
Zinus 14 Inch SmartBase Mattress Foundation / Platform Bed Frame / Box Spring Replacement / Quiet Noise-Free / Maximum Under-bed Storage, Twin XL They're a little low to the ground, but that's okay. The storage underneath is great! The reason I didn't give 5 stars was our delivery process. I ordered two mattresses and was told they were both in stock. However, when we got the shipping notification, they had been split into two different shipments. We got one, but the other one just hung out in cyberspace saying it was due to arrive on a date that had already passed. I contacted Amazon customer service and they recommended we cancel that one and reorder. We did that and then finally received the 2nd mattress about a week later. Since I was so unsure of getting the 2nd one, we didn't unpack the first one when it arrived (we needed two to make it work for our boys). By the time the 2nd one arrived and we unpacked, the first one had been in its box a little too long. It did "decompress," but not to the same extent that the 2nd one did. It's close, but it is definitely thinner than the other one. So, make sure you unpack them immediately; they don't like to be in their boxes for long.