Hi IrishRose,
I’m glad you found us before you pulled the trigger 
The first place to start is post #1 here (which it would probably be safe to assume you’ve read since this is the same thread :)) which is the single most important post in the forum and includes or links to all the basic information, steps, and guidelines you will need to make good quality/value choices (and just as importantly, know how to avoid the worst ones).
This is fairly typical of the types of comments that are so common all over the internet (or reviews from consumers that don’t really know the specifics of what is in the mattress they are reviewing) which can be very inaccurate or misleading … and confusing. There are many factors involved in the sleeping temperature of a mattress besides just the type of foam used which you can read about in post #2 here but of the three main categories of foam (polyfoam, memory foam/gel memory foam, and latex) … latex as a category is the most breathable and in general sleeps the coolest.
Of course all foams are insulators compared to natural fibers so if you have upper layers of any foam that are too thick and soft or if they are covered with less breathable synthetic quilting or covers or less breathable mattress protectors or sheets then these will all raise the sleeping temperature of a mattress no matter how breathable the layers below them are.
Some of the better options and possibilities I’m aware of in the Cincinnati area (including Covington/Florence) are listed in post #212 here.
Phoenix