Hi trevorreznik,
The first place to start your research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines that can help you make the best possible choice and purchase a mattress that meets all your criteria … and more importantly learn how and why to avoid the worst ones (including all the major brands and both stores that you mentioned).
Once you have done some initial reading and reach step 3 … if you let me know your city or zip code I’d be happy to let you know about the better options or possibilities I’m aware of in your area.
Phoenix