I own the G502 and I've recently switched to the Razer Deadadder because I found one in my university's library. So I decided to try it out and I find the deathadder way better for aiming but my movement is better with the G502. That might be because the deathadder has the right click slightly broken.
The G502 is heavier but it's also a lot smaller. So it all really depends on you specifically.