Hi mermla,
Degrees of softness and firmness are completely subjective and relative to each person’s perceptions and to the type of softness they are most sensitive to (see post #15 here). For example people who move a lot may be more sensitive to how fast the memory foam responds than to its actual softness or firmness and those who move little may be more sensitive to how well the mattress conforms to their sleeping positions and how it feels when they are still. If you move quickly the uncompressed foam can feel firmer until it softens and conforms to your body shape (like the difference between slapping honey and pressing slowly into it).
In general the Tempur HD memory foam (7 lbs) will feel softer and is more conforming than the same thickness of Tempur 5.3 lb memory foam so the Rhapsody will feel softer. They rate the Contour select as “extra firm” and the Rhapsody as “medium firm” so this would be two steps on the scale apart (with firm in the middle). How much difference this actually translates into for each person’s perceptions in different sets of circumstances and environments can vary widely.
The Beautyrest Black models are certainly their most costly models but once again they don’t disclose the density/quality of the foam and if you were to open it up and weigh each layer to find out it’s density (which some people actually do) you would discover that it had far too much lower density/quality polyfoam and memory foam in it to justify their prices or to have any reasonable expectation of good durability. Without knowing the specific quality of all the layers and being able to identify the weak link of a mattress (the layers that will soften and break down first which are almost always in the comfort layers of a mattress) there is no way to know the quality or durability of any mattress and “quality” becomes just a meaningless word used to describe high prices. When there is more than around an inch or so of polyfoam or memory foam in the upper layers of a mattress and you aren’t able to find out it’s density then it’s always safest to assume that at least some (too much) of it is lower quality/density and 9 times out of 10 you will be right … even with the most expensive mattresses (and certainly with the Beautyrest Black line).
Phoenix