Took the seat from my oilhead into a local shop run out of a guy's home, having the foam replaced with a gel insert, and then covered with a 'carbon fiber' look breathable vinyl cover.
I've heard comments on gel inserts or pads just not living up to people's expectations.
After visiting this shop, I have found the most probable cause for these complaints.
The type of gel that is used for the most part is pretty pathetic, he had the gel insets from Sargent, Russell, and a few other well known brands, and at best the gel was 1/4-5/16 ths of an inch thick, and was of a too compliant consistency, you could almost poke your finger through them.
The type of gel that he uses is an orthopedic gel, I guess somewhat similar to the gel inserts for shoes, it's 5/8ths of an inch thick.
So if you have a seat re-done, and want a gel insert, check to see what kind of gel is being used, before committing to having it done.
The R65 seat is in need of a re-cover as well, this relentless sun in Phoenix really is tough on seats.