Tempur is a petroleum product and Latex is a natural product - in case that matters to anyone. Tempur and all similar foam products will off-gas for a while - some people are sensitive to this even after years of use.

I think the heat issue you see a lot of complaints about with Tempur and similar products can be managed through different coverings. Even on a traditional fabric-covered sprung mattresses, different sheets can breath completely differently and affect your comfort level.

My favorite so far has been a memory foam layer on top of a multi-layered latex base. Latex will not break down and lose shape like the cheaper foams used on some "memory foam" products. Even on a real "Tempurpedic" product of say 12", not the entire 12" is made from Tempur.