Hate your mattress? Don't know what to buy? There is a solution.
Build your own.
A mattress is very simple. There is typically a base support which shouldn't ever deform and comfort layers on top.
I came up with a support system that will not deform. It is an air mattress that I reinforce with a six sided cover. The cover is smaller than the fully inflated air mattress. No holes, no stretching. I call it the tensioned mattress cover and a quick Google search will provide more information.
Support base achieved.
Now a topper. Foam by mail will lead you to every topper imaginable. My recommendation is 2" memory foam.
That's it! Everything is replaceable and only costs a few hundred instead of a few thousand. Many better places to spend your money then a hyped up mattress that breaks down after a few short months.