Now 722 i said they were great in the mud. i watched a guy go through a hole that we all had to winch out of, polaris included. he just played in it and made us all shake our heads. it' s that diff. lock!
and i know one guy that has one that has been to he** and back and still going.

I wouldnt buy one though. my kawasaki has an unknown amount of miles. it is a 92 and still going. i have had to do a lot of repairs to it. i can' t keep water out of the front end. i have change every seal and vent hose several times. but it is still a dependable wheeler.
i hate to say this but it really is preference. and a very important factor in how long anything lasts is maintenance. and how it is ridden.
you have to take care of them. i just did my spring oil change on my honda last night. i change it every spring and fall whether it needs it or not. i also change the front and rear oil. make sure it has a clean air filter and really inspect the machine after i ride. if it is broke i fix it.
if you do these things i think most major wheelers will last.
And with as many zerk fittings as a polaris has you probably will spend a lot of time greasing!