Hi mmeursaulkt,
Welcome to the Mattress Forum! 
I’m guessing you’re referring to the Brooklyn Bedding Best Mattress Ever (BME) in a medium. The BME uses 2" of blended Talalay latex over 2" of synthetic Dunlop latex over a 6" HD 2.0 lb. polyfoam core. The mattress uses good quality materials and would be appropriate for most any weight range. The BME is offered in three comfort choices and offers a 120 night sleep trial.
The Ghostbed uses 1.5" of synthetic Dunlop latex over 2" of 4 lb. memory foam over a 7.5" HD 2.0 lb. polyfoam support core. They are certainly using good quality materials and there are no lower quality materials that would compromise the durability or useful life of their mattress for those that aren’t in higher weight ranges (more than about the lower 200’s or so) where I would reduce or minimize the use of 4 lb memory foam. They offer a 101 night sleep trial.
You can see some comments about the type and quality of the materials in the Ghostbed along with many of the other what I call “simplified choice” mattresses in post #2 here and the first post in the same topic would also be well worth reading as well.
Brooklyn Bedding, who makes the Best Mattress Ever, is a member here, which means that I think very highly of them and that I believe that they compete well with the best in the industry in terms of their quality, value, service, knowledge, and transparency.
While I can certainly help with “how” to choose … It’s not possible for me or other site members to make specific suggestions or recommendations for either a mattress or how one compares in feel to another, because the first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components or which type of mattress would be the best “match” for you in terms of “comfort”, firmness, or PPP (Posture and alignment, Pressure relief, and your own Personal preferences) or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress), sleeping positions, health conditions, or “theory at a distance” that can possibly be more reliable than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here ).
As for the BME, I would take the time to place a phone call to them and describe to them your sleeping posture and mass, and see what their recommendations are in their lineup (Firm or Medium). They would be best able to advise you as to which product they offer that might best work for your situation. The Ghostbed is only offered in one comfort.
Regarding temperature, while it’s not really possible to quantify the sleeping temperature of a mattress for any particular person with any real accuracy because there are so many variables involved including the type of mattress protector and the sheets and bedding that you use (which in many cases can have just as significant an effect on sleeping temperature as the type of foam in a mattress) and on where you are in the “oven to iceberg” (oven for you) range and because there is no standardized testing for temperature regulation with different combinations of materials … there is more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range.
With that being said, Talalay latex is generally the most breathable foam, followed by Dunlop latex, polyfoam, and then memory foam. The BME would tend to move air better through the comfort layers than the Ghostbed, as that product has 2" of memory foam directly beneath the upper latex layer.
There really are entirely too many variables, unknowns and personal preferences for someone else to make specific suggestions for you on how one mattress will “feel” compared to another or how warm it will sleep for you. However, there may be some site members who have tried both products and their comparative statements might be useful to you as you go through your decision-making process.
Phoenix