Good for another ten years!
At least ten years ago I bought a mattress from sleepez.com, guessing at which layers would work. I was able to get reimbursement through my Flexible Spending Account, with my allergy doctor's prescription. I used the firm on top.
Because I sleep at the edge of the bed, the sides were a bit worn down. I just bought an extra firm layer for the top layer, and the bed feels like new again. The cover looks almost new, with that amazing heavy-duty zipper.
I removed the soft layer and it is now a topper for a rock-hard futon. I also received a latex pillow, and after removing about a third of the filling, as directed, I'm loving it. Someday will buy the wood slat foundation, when funds allow.
It's a first-class company with first-class products.