screw polaris, the newer ones turn to crap real quick if you abuse them or take them away from stock form and put more stress on the stock parts. Now, back in the day, like the late 80's and early 90's, those will take a beating like no other, the new ones just don't have the durabilty or reliability they should from what i've seen. At the local shop nearly half the quads i see there for service are polaris, and they probably only account for about a tenth of the quads around here.
I'd stay away from suzuki too, i've seen too many design flaws in them as well. They're generally good machines except they're not as refined as a yamaha or honda, and usually have a lot of little stuff that needs redesigned or modifed to make them work right, even stock.
You could make a pretty badass ride out of one of the 4x4 350 wolverines, the pre-automatic models. I can't stand to look at the new ones, they're an embarrassment to the yamaha name in my opinion.