Hi chip,
I probably wouldn’t make that assumption although it could turn out to be correct. I would call the ones that are possibilities and give them your criteria and see if they have any mattresses that they carry that fit them before you visit them. Dixie foam would certainly be among the best quality/value in the area IMO.
A mattress is only as good as the quality of the materials that are in it so you would need to know the details of its construction and the density of the foams inside it to make any meaningful assessments. Memory foam mattresses range from cheap junk that are often made in China that use filled memory foam to make the density appear higher to high quality and more costly mattresses that use higher quality North American or CertiPur certified foams and everything in between. You can see the criteria I use for memory foam mattresses in post #10 here. If it meets the criteria and you are confident in the accuracy of the description and the knowledge and integrity of the retailer … and if it meets your needs and preferences in terms of PPP (Pressure relief, Posture and alignment, and Personal preferences) I would consider it. If it doesn’t meet these criteria I wouldn’t.
Phoenix