These are good, but in my case they couldn't beat a setup that is an order of magnitude cheaper, simpler and better. A simple custom-made japanese shikibuton, filled with felted wool panels and a buckwheat pillow. I put this on a modular set of bed slates to avoid insects, get better airing and avoid cold floors.
I treated a few years of my life as an experiment to improve my sleep. I bought a Hästens and that latex IKEA mattress. I used them for 3 years, switching back and forth every 6 months. Then I made this custom shikibuton, and after a few months I never looked back.
There is some literature which explains how we evolved sleeping in relatively firm setups. Big, expensive and mushy mattresses tend to be a bit too soft and you end up developing neck aches as I did. A better option is just some slightly flexible wood base, or a tatami, and some thin cushion. In fact, another less unconventional setup I like is a horsehair topper, like one of those from Hästens, on top of some wooden base.
My shikibuton is really cheap. It's washable! I can open my futon, put felted wool panels in the washing machine and it's dry in a day. It's very comfortable. It's ended up my perennial neck issues. It's convenient, I can transport the whole system in my tiny car.
A simpler, non-washable alternative is to have a big cover filled up with buckwheat hulls. Every 6 months, compost hulls, buy new ones, and wash cover. Every month, empty hulls into a bag and wash cover.
I don't understand why this alternative is not more popular in the West.