Hi BobinCA,
I switched your post into a new topic of its own because it wasn’t related to the topic you originally posted in.
There is more about the 3 most important parts of the “value” of a mattress purchase in post #13 here which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on suitability, durability, and all the other parts of your personal value equation that are most important to you (including the price of course and the options you have available after a purchase if your choice doesn’t turn out as well as you hoped for).
I can’t speak to how any mattress will feel for someone else or whether it will be a good match in terms of comfort, firmness, and PPP (Posture and alignment, Pressure relief, and your own Personal preferences) because there are too many unknowns and variables involved and you are the only one that can feel what you feel on a mattress.
Outside of PPP (which is the most important part of the “value” of a mattress purchase), the next most important part of the value of a mattress purchase is durability which is all about how long you will sleep well on a mattress. This is the part of your research that you can’t see or “feel” and assessing the durability and useful life of a mattress depends on knowing the specifics of its construction and the type and quality of the materials inside it (see this article) regardless of the name of the manufacturer on the label (or how a mattress feels in a showroom or when it is relatively new).
In terms of durability (which is a completely separate issue from the suitability of a mattress and whether it will be comfortable and supportive) … as you can see in the quality/durability guidelines here, the top 3 1/4" of the mattress are much lower quality and less durable materials than I would suggest … especially in your weight range … and I would avoid it.
The major brands such as Sealy/Stearns & Foster, Simmons, and Serta all tend to use lower quality materials in their mattresses than most of their smaller competitors that will tend to soften or break down prematurely relative to the price you pay which is why I would generally suggest avoiding all of them completely along with any mattress where you aren’t able to find out the type and quality/durability of the materials inside it (see the guidelines here along with post #3 here and post #12 here and post #404 here).
Phoenix