My wife and I went through several mattresses with varying degrees of back trouble. We didn't buy that brand particularly, but we went with a memory foam mattress and it's made a huge difference.
We have had one for years now and love it. If you get a true Temper-pedic brand mattress they will not be hot.
There are only 2 places in the city that sell the true brand that I know of, Matthis brothers and Dane Design. My mother in law works for Dane design. If you want good info and to make a good educated decision without high pressure sales go in and see her.
Her name is Kandie, just tell her that her son in law refered you. They are off of Portland and Reno, on the North west side of the intersection behind that gas station.
My GF has one and I cannot get used to sleeping on it....It doesn't spring back fast enough for my comfort, I will lay in one position, turn over and its still in the last position. I suppose I will get used to it.
they are very hot .... dont need covers over you in winter with window open ...I have alot of back problems and this is the only bed that doesnt hurt me ....its a sealy brand but made just like tempur-pedic... yes they do keep your shape when you try to roll over takes a bit for it to raise up and mold to your new position