I bought a bed with a memory foam mattress a few years ago to help support my back. Didn't help & a few months later my Chiropractor said I should have bought a bed with a firm mattress! Still I can always buy a spring mattress later.
I found one thing that's good about it, If I have to get up in the middle of the night to go to the loo, when I get back in my bed its still warm (unlike my old beds) handy for cold winter nights.