Hi turbocats,
Welcome to the Mattress Forum! 
The “best” advice I can share is to make sure you follow all the steps in the mattress shopping tutorial one at a time which has all the basic information, steps, and guidelines that you will need to make the best possible choices and make meaningful comparisons between mattresses … and know how and why to avoid the worst ones.
Jamison is a smaller independent manufacturer and they tend to use higher quality materials in their mattresses than most of their larger competitors and would typically have “better than average” value but the value of a mattress purchase always depends on how well it matches your specific needs and preferences in terms of PPP, on the quality of the materials, and on how it compares to your other finalists based on the parts of your personal value equation that are most important to you. There is more about the most important parts of the “value” of a mattress purchase in post #13 here and the posts it links to.
There are also some other options in the Evansville area that would be well worth including in your research as well. The better options or possibilities I’m aware of in the area are listed in post #18 here.
Phoenix