Hi slain,
There is more information in post #2 here about various different types and combinations of gel materials. both of these are in category #5 which is a layer of solid gel used over either polyfoam (such as in the gold) or over memory foam (such as in the platinum). These would both be good choices although they are both a more costly topper as well.
Intelligel is also a gel material but it is what is called 'buckling column gel" which uses a different principle where the colums “buckle” under weight. There is more about these here (orthogel is also a similar buckling columm gel). Post #1 here also has more about the intellibed (a critique on their video) and a search on “edizone” (you can just click this) will bring up more information on the intelligel as well.
The Activus polyfoam and Aerus memory foam (both made by Foamex/FXI) that is used under the gel are both good quality materials although I would want to know the density of each.
Post #4 here has some sources for memory foam toppers.
The better options or possibilities in the Nashville area I’m aware of are in post #7 here.
Hope this helps. Thanks too for the links. I hadn’t seen them 
Phoenix