Hi beeks1305,
You can see some comments about some of the new breed of “one firmness fits all” mattresses along with descriptions of the materials they use in post #3 here.
A forum search on Leesa (you can just click the link) will also bring up more comments and feedback about them as well.
While none of them are actual manufacturers so they have an additional “middle man” compared to factory direct manufacturers that have their own factory and there is no such thing as a single mattress that “fits” everyone … they can certainly simplify the process of choosing a mattress for those who are more time constricted and don’t wish to spend the time looking for the “best choice” and a choice that is “good enough” is what is most important to them (and of course if it isn’t “good enough” then they all have a great return policy)
You can also see my comments about them relative to those in higher weight ranges in post #3 here.
I would be very cautious about the Leesa in particular because of the 2" of 3 lb memory foam they use which is a lower quality/density material than I would normally be comfortable with even in “average” weight ranges and even more in higher weight ranges.
Outside of the information in the mattress shopping tutorial which is the first place I would begin your research … there is also more information and guidelines for those that are in higher weight ranges in post #3 here and the posts it links to that will be helpful. The process of choosing a mattress would be exactly the same as for anyone else except you will generally need firmer mattresses and more durable materials than those that are in lighter weight ranges.
Phoenix