Looking for a New Mattress, HELP! Confusing World of Latex, Foam, & Springs. Tuft & Needle?

Our current mattress is an 11yr old Sealy Posturepedic pillowtop that has become uncomfortable. Grooves have formed over the years of where our bodies typically lie and the support just isn't there. My wife and I both prefer a firm mattress and are both side sleepers. Right now, I am torn between going with another old style of spring mattress or trying a memory foam type. That is where the confusion comes in. Looking online, there are several companies with very high ratings (Tuft & Needle, Casper, Leesa, etc) and it is really difficult to initially decide who to go with having never seen or laid on the mattress. The return policies look very good with all the foam style mattress companies so I don't feel that would be a major factor. I guess the benefits of going with a traditional mattress (Sealy, Serta, Simmons) is that I know what they are like and would be happy for a while (until the sag sets in eventually). The memory foam style mattress like a Tuft & Needle 10 inch uses their proprietary foam that has a 10yr warranty but i don't think there is a 10yr history on how that foam will hold up. the good news is that the Tuft & Needle 10 inch Queen mattress is very affordable at $600 compared to some similar mattresses at about $1000. I guess I have some more research and decisions to make before I decide what we will sleep on for the next 10 years....wish me luck