Hi SJS,
Post #2 here has more about making firmness or design choices and some of the theory behind it (including zoning). I’m happy to speak to the quality or value of a mattress and the materials inside it but design choices would depend on your own personal testing or on more detailed conversations with a manufacturer. They know more about their mattresses and which may be more suitable for different people and circumstances based on the “averages” of their customers that are similar to you than anyone else. Both of the choices you are looking at would make great choices in terms of quality and value.
Once you are comparing “good and good” (and both SleepEz and Flobeds are certainly in this group) then final choices would always depend on all the objective, subjective, and intangible the parts of your personal value equation that are most important to you.
More layers can certainly provide more design flexibility and options but this may also become more complex and not necessary (see post #2 here). The Flobeds customized vZone is also a good option for those who need it because it can vary the support or softness under different parts of the body to a greater degree than just the natural properties of latex itself (see this article and post #11 here and post #10 here about zoning) for those who need the additional flexibility of custom zoning.
Hopefully this will give you the information you need that along with your more detailed conversations with each can help you decide which is best for you.
Phoenix