Hi Marthalawlor,
Royal Sleep Products in Fort Worth does business as City Mattress Factory and you can see some of my thoughts about them in the Dallas/Ft Worth list here.
In terms of quality/durability though, a mattress is only as good as the quality and durability of the materials inside it regardless of the name of the manufacturer on the label and the mattress you are looking at uses 12" of Talalay latex (the description isn’t clear about whether it’s 100% natural or blended Talalay but both are good quality materials) so there are no low quality materials or weak links in the design.
If you have tested the mattress carefully and objectively and it’s a good match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) and it also compares well to your other finalists based on the parts of your personal value equation that are most important to you then it would certainly be well worth considering as your final choice.
Phoenix