The G502 wheel was too clunky, heavy and had too much play due to the weight.
I had the G700 before and basically, the same scroll wheel is used in the G700 and G500 except one is shiny and one is matte.
The G700/G500 scroll wheel is lighter, has the rubber strip in the middle and the clunky bump, while scrolling, is less pronounced.
Basically imo, it is more comfortable to use and quieter.
It is a easy drop in mod, so I recommend it if you dislike the G502 scroll wheel.