ShiftapowergamerI'm in the same boat as flatline with my g500 of 4+ years starting to have slight noticeable issues on the right mouse click.
I'm thinking about just buying another g500. Obviously quality for fps is important, but I also use the scroll wheel left and right click binds for going forward and back for things like webpage browsing, which at this point is too ingrained in me to want to get another mouse that doesnt have that functionality.
Try the g502. Similar shape, has the left/right scrollwheel buttons and good sensor. It's relatively heavy but if you use a g500 you're used to that now anyway.
I've also been looking at the g403. I am really torn between the g403 and the g502 right now. If only the 403 had the scroll binds I would be sold instantly. While that is important I'm worried that giving up performance that the 403 or other mice like zowie mice may be too important.
edit: just bought the g502, wish me luck