I personally would go with the Superwinch. Here's Why : I'M CHEAP!!!. The Warn is around $300.00 for the 2000lb model. I have seen it slightly cheaper but I have also seen it much higher. The Superwinch ATV2000 can be had for $169.99 (the T1500 model can be had for $119.99. I have owned the T1500 and it worked fine for me even after being submerged a number of times. I could almost buy 2 of the Superwinches for the price of the Warn. Maybe the warn will last 10 years, but I doubt i'll own it then because I don't keep a quad that long and I don't take the winch off when I sell it. That's just my reasoning, as flawed as it may be.
Good Luck with your selection.