Buy the one that you can get the best local dealer support from after the sale. Example - The evening before I left for our last trip, I needed a throttle cable for the M8. My dealer didn't have one on the shelf and took one off a new sled they had on the showroom floor - all this an hour before they closed for the holidays.
Another is buy the brand all your buddies have - Sharing belts or other spare parts on the side of a mountain is much easier when you're all riding the same thing.
There is a lot to be said about dealer support and friends. These two combined will give you more riding time.