I have a thread asking the same question with a bunch of responses.
This is a Maverick forum, they are all going to say Maverick. RZR Forum will all say RZR, Cat forum will all say Cat. Nobody wants to spend $15-20k on a machine and say it sucks and that you should buy something else. The question you should ask is WHY you should buy machine X over the others. Every machine has its pros and cons.
While that may be true because the people on this forum are Can-am owners, I will tell you to buy what you feel comfortable. If you buy the 1000 XP, know that there will be something faster next year. There is no way around it. You will have the latest and greatest for 6 to 11 months then you will be outdated. The SxS industry has become as bad as the computer industry. You can't stay on top for more then a few months. I am a little disappointed, as I have said before I was one of the first west coasters to get a Commander which was top dog for about 4 months. Then I was one of the first west coasters to get the mav which was top dog for about 9 months.
Again, I have resigned to the fact if I sell my mav and get a 1000 XP, by this time next year something will be faster. I am really interested in the Wildcat X for next year, I think Arcticat will step up and beat both can-am and polaris. I really want Kawasaki to get in the high end SxS game. I think they would work everyone in high end SxS's. Until then I am really happy with my Mav, it's fast, has great suspension and is super comfortable.
The fit and finish on the can-am's are hands down better then the XPs period. I like the suspension and foot print design on the Arctic Cat the best, I think with a little tweaking it will really be awesome. Most of all the power on the 1000 XP is bad ass, if you could meld the 3 you would have a super SxS.
Good luck with your choice, I don't think you would go wrong with any of the 3.
Dennis