Having bought a mattress recently, it might be worth going to a mattress store. The sales process sucks, but if you want to find a mattress you like, it's hard to beat actually laying down on one.
It also can help you identify the kind you like (coil, latex, etc) and composition you like (layer style and thickness).
Then you just search for those two things online.
That's how I found an amazing natural latex cooling mattress online.
And the best part is that most online mattress retailers have 90 day try out periods. We didn't like our first one, and instead of having us ship it back they told us to donate it and sent us the next to try. So now we have a really nice spare bedroom mattress as well as the perfect mattress in our bedroom.
