i will assume your talking about the wildcat?
i will give my 2 cents but only because of my history with cat.
i have owned AC all of my adult life pretty much. 2-400's 3-H1's a prowler and a 500. i also used to do warranty work for steel horses.
the BEST thing about the WC is its suspension. AC really out did themselves in that department... BUT it has basically the same old diffs. weak. they have several known issues and not the best EFI system since they do not use a tmap sensor. they also have a SLD which is junk.
many folks get random EFI codes that really don't exist.
here's a fun little thread from earlier this year...
Beware of engine problems and poor customer service - ArcticChat.com - Arctic Cat Forum
i am still the owner of 2 cats... the H1650 in my sig and i have a 300 4x4 for a dedicated water bike. BUT, they are both carb'd bikes for a reason.
and customer service/ warranty issues are only as good as your dealer. most folks don't understand that you can use ANY dealer you wish for warranty.
this is my first polaris to own and i have to say this new EFI system is TOP NOTCH. the diagnosis system is second to none. show me another atv manufacturer that non only shows the sensor at fault BUT the exact wire(s) at fault just from reading a number on the pod.
like is said. if anyone is die hard AC, its me. but cat simply done nothing to step up their game in the drive train department besides a more powerful engine. that's like putting a bandaid on a broken leg.
other things to consider...
the rzr's stator output is significantly more than a WC
the wildcat will make way more ground clearance with factory suspension
the WC really has no front end protection. i have seen tires/ hubs ripped clean off
the WC has WAY lore leg room ( thats what i liked the most)
i hope my opinion helps. i only like to comment on things i have experience with and i have about 7 years under my belt with cat so i hope this sheds some light.