First of all, this arrived super-fast. Second, it's an incredibly comfortable and high-quality mattress, especially at this price point. I put it on my platform bed and slept like a baby from the first night. That said, a few things to be aware of:
1) The mattress arrives rolled up like a sausage, encased in layers of shipping material. It took me literally 40 minutes to get it out of the packaging. First, you need pliers to cut through the wire that binds the outer shipping bag. Then, you need a sharp knife to cut through the two layers of super-thick plastic sealing around the mattress. This thing is like government-sealed. I guess this is good, in terms of protecting the mattress, but be prepared for a struggle.
2) I ordered a medium. When I first lied down on it, I thought, "Oh no -- this is too soft. I should have ordered a firm." But within a few hours, when the mattress expands to its full size, it's PERFECT. Supports my back, but also so accommodating when I move from position to position. But if you're someone who likes a firmer mattress, definitely go for the firm.
All in all, I highly recommend this to anyone looking to replace their old-fashioned, wire-coil mattress.