i use a deathadder myself though i did try out the g502 for a few days. the sensor worked great, weight was great and the button layout was comfortable to use. i do not care for hyperscroll and the clicky scrollwheel option made it feel clunky (ymmv). the mouse was a little narrow for me since i normally use the wider deathadder. i did end up returning it and getting another deathadder because it did not quite fit my hand and i did not like the scroll wheel, everything else on it though was great (that and i managed to get it for $30...
tldr; if you do not mind hyperscroll or the clunky scrollwheel and do not need a super wide mouse it is not bad.