I've gone through two beds in 5 years. One bed had all the springs on one side so you don't have to flip it. I had a dip on my side within 3 months. The one I'm on now was fvckin great for a while but now there's a dip and it gets worse every month. It's got the pillow top and all.
The memory foam ones have always felt uncomfortable to me. I prefer a soft mattress that stays cool. I just saw a commercial for the Dormeo Octaspring and it looks comfortable as shit. Anyone have experience with it?