On pretty much any 'painted' mouse or device that's being used constantly you'll eventually wear-off the paint. I'm more concerned about if it works and works well.
Personally, I'm very finicky about the 'feel' of the keyboard and the key strokes. While 'my feeling' works for 'me' it might not work for you. Therefore, I've found it best to go to a few places that carry PC stuff and tryout the KB/M. Next, I have specialized KB/M for different purposed uses.
This is like trying on shoes and how it fits; good for one horrible for another. In general, I find to a degree you get what you pay for, and there's nothing worst than a 'poor fit.' Gaming USB IMO is a must over anything wireless. Illuminated is a necessity if you need to look at the keys.