Hi persephoniekali,
the first place to start your research is the tutorial post here which has all the basic information, steps, and guidelines that you will need to make the best possible choice … and know how to avoid the worst ones.
Outside of careful and objective testing for PPP (Posture and alignment, Pressure relief, and Personal preferences) using the testing guidelines in the tutorial post, the most important part of a mattress purchase is making sure you know the quality of the materials inside a mattress so you can identify any potential weak links and make more meaningful comparisons to other mattresses (see this article and the guidelines in post #4 here).
If you can find out the specifics of the materials inside the Stress-O-Pedic you are considering and post them here (and as you can see in this thread Stress-O-Pedic will provide them to your retailer), I’d be happy to make some comments or help you identify any potential weak links in the mattress.
The tutorial post also includes links to several lists of some of the better online options I’m aware of including many of the members of this site.
There are no members of the site in your immediate area but some of the better options and possibilities I’m aware of in the Santa Barbara / Ventura area are listed in post #2 here.
Phoenix