Fairly abusive to my previous 02 Yamaha 660 Grizz and my current 06 Yamaha 450 Kodiak with ZERO problems. Use mine less and less for hunting, but rarely take them where they stay on all 4 wheels for long when I do. Biggest issue is they get colder blooded the older they get, but if I keep tanks filled on cold nights they always start.
My dad and frinds have Polaris, but they seem awful heavy and not as nimble, plus hate their full time 4wd crap, I prefer to push my little button when I need it.