FWIW I shoot competitively and with guys that shoot anywhere from 200-500 arrows a week. All that handling takes a toll and they all, to a man, shoot black bows. It also seems that black bows are easier to re-sell if that makes any difference. All my current bows are black with the exception of a Mathews Halon X Comp I just traded for thats white. I know the guy that bought the bow new and how long he had it and honestly it looks dirtier than a black Halon X that I have that's older than it it is.
I have all black bows - If you hunt hard, and you hunt spot and stalk more than tree stand hunting then the bow will be dirty looking all the time. Just wipe down with a damp rag and you will be good to go after you get back from a successful hunt!
Personally I don't mind scratches on my gear, unless it involves optics. It's going to take a decent scratch to get through he paint on any bow. I have a black bow and the only potentially bad thing I would say is if it's left out in the sun it can get hot a little bit faster than others.
I hunt with a black Halon 32 and while it may show dirt easier I like that if I ding the riser or limbs a black sharpie covers it up well enough to where it wont bug me.