Hi ab54smith,
The feel and performance of a mattress will depend a lot on all the layers rather than just the memory foam and layer thickness and the type layers over and under the memory foam will make a big difference in how each mattress feels and performs. There are hundreds of different types of memory foam (with many different qualities and differences in how they feel and perform and “firmness” levels) and gel memory foam is just one of them. Gel tends to make the memory foam firmer (and there are other ways to do this as well) and the gel is also convective which means it can help reduce sleeping temperatures (and there are many other ways to do this as well). there are also better and worse versions of gel formulations although there is not a lot of information about the comparative differences between the different types and you have to dig fairly deep to find this type of information. There is more about the different types of gel memory foam in post #26 here.
The Dreamfoam mattresses are made by Brooklyn Bedding which one of the manufacturer members of this site (which means that I believe they are among the best quality/value available) and they have a complete description of the specs on the Amazon site (the queen is listed here for example). They list the type of latex in the comfort layers, the density of the polyfoam base, and use 1.5" of supersoft polyfoam in the quilting and have a bamboo ticking. These are all the essential specs and indicate high quality materials.
Like all the business members here … they also provide a bonus or discount to all the forum members who purchase a mattress which in the case of the Dreamfoam is a free shredded latex pillow if you let them know your username here. They also give their customers a choice of different firmness levels of the latex.
The guidelines are based on averages and will of course vary with the other layers of each mattress but in general terms people who are heavier and side sleepers will tend to need thicker and/or firmer comfort layers. Talalay latex is the coolest of the foams and supersoft quilting foam is also very breathable. There was a post today (post #14 here) from a member who just slept on one for the first night and remarked on how cool it slept for him.
Of course as with all things … there is always a tradeoff in buying online vs locally because your choices are based on “theory” and you don’t have the chance to test the mattress (or return it in this case) so it’s a little riskier unless you have tested latex in similar layering.
Hope this helps.
Phoenix