Hi mike7,
Thanks for your feedback about the Beautiful. It certainly is a soft mattress and would be too soft for some people and of course just “perfect” for others.
In terms of quality and durability a mattress is only as good as its construction and the quality of the materials inside it. Unfortunately you won’t be able to find out the quality of the materials inside the Beautyrest Black and in most cases they would include lower quality foam in the comfort layers which would make it a risky purchase that I would avoid (see the guidelines here). As far as the Tempurpedic … it would depend on the specific mattress you are considering. Most (but not all) of the Tempurpedics use good quality materials but without knowing the specifics of all the layers in a mattress and their quality it’s not really possible to identify any potential weak links in the mattress or make any meaningful comments. Post #2 here also has links to several forum posts with more detailed information and thoughts about the Tempurpedic line.
As far as the suitability of a mattress or PPP (Posture and alignment, Pressure relief, and Personal preferences) … there is no formula that can predict this and your own personal testing and sleeping experience is the only way to know.
Phoenix