We recently purchased a new Sleep Innovations 12-Inch SureTemp Memory Foam Mattress
mattress. Kohl’s was running this great sale on a Sleep Innovations mattress, but their website was not working correctly. We ended up buying it from Amazon (free shipping!). It took about a week to adjust. The memory foam is a bit more firm than our worn down spring mattress. After a week, I’m sleeping better. Personally I think it’s a bit warm compared the old Sealy. I have not noticed it being warm after summer left.
Edit: After a few months of usage, my wife has determined that it makes her overly warm. If you lay or sit near the edges you also sink a quite a bit, you can’t really lay off the edge. The mfg will only honor the warranty if you put a water proof cover over it.
