Hi muncher,
Unfortunately, there are too many unknowns, variables, and personal preferences involved in choosing a mattress for me or someone else to make specific suggestions based on specs (either yours or a mattress) or theory at a distance that can possible be more accurate than your own careful and objective testing (using the testing guidelines in the tutorial post) which is always the most reliable way to predict which mattress will be the best match for you in terms of PPP (see mattress firmness/comfort levels in post #2 here).
The Best Mattress Ever does offer three different combinations of comfort (plush, medium, firm), and the upper most layers are two 2" layers of Talalay and Dunlop latex, respectively. This will tend to have a bit more of a “buoyant” feel on top.
The KISS mattress comes in one firmness option and uses 1.5" of Talalay on top, under which is 1.5" of a HP polyfoam which has some of the conforming properties of a memory foam without the feeling of sinking in too much (a bit more resilient than memory foam).
Overall, both items use good quality materials that would not be a cause for concern for your BMI (both use 2.0 lb. polyfoam cores). The BME does have 1" more of “specialty” foam in the upper layers. Objectively, both items spec out well for the price point they’re offered. The only reliable way to tell if you liked one of these better than the other would be through your own careful personal testing. You are dealing with two good companies (Brooklyn Bedding and SleepEZ are both site members here, which mean that I think highly of them), and both options have good return policies should your decision not turn out as well as you would have hoped.
I’ll be interested in learning what (if anything) you decide to choose.
Phoenix