Hi metsfan,
The two best suggestions I could make are about what to avoid and what to include in your research.
This article should help you avoid most of the worst choices.
A list of the factory direct outlets near you (and you have some great choices) is in post #2 here and these are your better choices.
Post #2 here includes links to some of the forum feedback about some of them as well.
The most important first step in finding a great mattress is to first find the best outlets. Once you’ve done this … over half the work is done and making better choices between mattresses that all have better quality and value and with the help of people who really do know their stuff is much easier than trying to wade through marketing claims and never knowing what is true or being unable to find the type of information you really need to make good choices and meaningful comparisons.
You’re fortunate to have as many good choices as you do 
Phoenix