Absolutely love this mattress. It seemed a little more firm for my liking at first, but I have not woken up with a single backache since I started sleeping on it. I used to toss and turn all night and wake up aching every day.
I am extremely pleased with the mattress so far, and how easy it was to get (no rental truck, etc). However, I have not had enough times to know if it will hold up. If it stays the course and holds up well then I would certainly recommend it to a friend, if they ask about mattresses.
Was starting to develop back issues from the blow-up mattress I was using for a few months. After the first night the pain was 90% gone. After the second it was completely gone. The mattress does retain heat very well but personally i don't consider that a negative.