Lol mice and keyboards shouldn't have any affect on your skills, just sayin.
I don't care for the R.A.T. line or G500 for the same two reasons: Sensor choice and weight. The Twin-Eye in the R.A.T. has Z-Axis tracking issues and the ADNS-9500 in the G500 has positive acceleration (and negative on cloth pads).
The G500 also has an off-center sensor which can be annoying to some.