Hi kgallenbeck,
I switched your post to a new topic of its own so it wouldn’t get mixed up with another member’s topic.
The first place I would start your research is the mattress shopping tutorial here which has all the basic information, steps, ad gidelines you will need to make the best possible choice … and know how and why to avoid the worst ones (including all the manufacturers you were mentioning along with all the other major brands or any mattress where you aren’t able to find out the type and quality of the materials inside it … see this article).
The better options or possibilities I’m aware of in the Phoenix area (subject to the guidelines here) are listed in post #4 here. You are very fortunate to live in the area because 4 of the manufacturing members of the site are based there and you have the chance to test their mattresses in person while most of the forum members can only order them online.
Phoenix