Hi remops,
I’m not sure what he may have meant by saying the 2.17 lb foam was the issue unless he knows the IFD (firmness/softness) of the Jamison foam because foam density and foam softness are not closely connected. 2.17 lb foam can have a wide range of softness levels from very soft to ultra firm … all in the same density. Density does have some effect on the compression modulus of a foam (which is the rate it gets firmer as the foam is compressed more) but not on the firmness rating itself.
I am one of those who like the “feel” of latex over memory foam but like any combination of layers how it feels will depend on the specific firmness of the latex, the type of memory foam, and on your own individual perceptions and preferences. Perceptions of softness and firmness and the “feel” of a mattress are subjective and can vary widely between different people on the same mattress depending on the body type, sleeping positions, and individual perceptions of each person. One person’s “soft” is another person’s "firm.
At the end of the day … only your own personal experience (either before or after a purchase) can really know how a mattress feels to you and theory at a distance is only based on “averages” that may not apply to any specific person. If you test a mattress in person then of course you would know how it feels and performs if you do some careful and objective testing. If you are ordering a mattress online that you haven’t tested … then the manufacturer will often know how their mattress would compare to other mattresses that are widely available locally for most people but this introduces some subjective elements into the picture and a mattress that feels very similar to 9 out of 10 people may not feel the same as a mattress you tested for the tenth. In this case or when you have no experience with a specific design then the return policy of the retailer or manufacturer or the ability to make adjustments to the mattress may be an important part of each person’s personal value equation. There is more about “matching” one mattress to another in post #9 here and about making comfort choices based on theory or specs and some links to some of the “theory” involved in mattress firmness/comfort levels in post #2 here but these are only generic and not specific to any individual person. It takes many years of experience and knowledge of foams and components to be able to predict how a mattress may feel and even the best manufacturers are often surprised at how a design for a new mattress doesn’t feel the same in real life as they thought it would “in theory”.
In other words … your recourse after a purchase if you design or choose a mattress that you haven’t tested and doesn’t work out to be close to your ideal may be an important part of your purchase decision.
The good news is that you are looking at final choices between good and good in terms of quality and value which is a great position to be in but your own experience will be the only way in the end to know if the mattress is suitable for your specific needs and preferences in terms of PPP 9Posture and alignment, Pressure relief, and Personal preferences).
Phoenix