The G502 is too heavy, specially for FPS gaming.
I recommend you also check this list out: http://mousearea.com/best-csgo-gaming-mouse-2016/
Peronally i reccommend the FinalMouse 2016, i has the best sensor in the world.
"The G502 is too heavy, specially for FPS gaming."
For you maybe. Everyone else: whatever they prefer. Having a lighter mouse isn't necessarily going to make you objectively better. Any mouse with a perfect sensor, like the G502 or Finalmouse, is a great mouse, worthy of any recommendation.