I have a Tempurpedic mattress, one of the less expensive ones. I like it a lot. It is not the solution to all my problems, but I'm pretty sure no mattress will solve everything.

Before I had this mattress I had a futon on a platform bed. The Tempurpedic is better. Futons are comfortable but they develop a ditch after a while.

My advice would be to go to a store that sells a wide range of models and try them out. In this area we have Healthy Back stores where you can lie on a mattress for as long as you want to decide if it's comfortable for you, and they have many different models to choose from.

FWIW I use mine on the same Ikea platform bed frame that I used with the futon. I bought two sets of slats so that there are not gaps between them.