Glassy, there is so much more I could share. How deep into research do you like to go? I read as many independent reviews as I could. Wirecutter, Sleep Foundation, even Good Housekeeping.
YS is a scientist so he's a research pro. He relied on the reviews of the first two I mentioned above, then selected those to read more in-depth info. Note that most of the time, only one style of mattress for each brand is reviewed. For example, the Saatva reviews were for the Classic, not the Latex I chose in the end. Based on what he read over a month's time last spring, he recommended looking at several online, direct-to-consumer mattress companies. These included Helix, WinkBed and Awara in addition to Saatva. Pros and cons to each. Sometimes the only con is price. No one right mattress for everyone, of course. (I like it better when there IS one best choice.) So many variables. Side sleeper, back sleeper, stomach sleeper. Hot sleepers. Cold sleepers. Firmness. Materials used. Variations within each type: innerspring, foam, hybrid. The list goes on...
Good luck to you!
Q