there are a few issues with the 900 but overall it is a good strong motor. if you are buying the sled used the first thing i would do is take the engine out and get the big boy bearing kit on it right away. then when you put it back in make sure that you get the engine stablizer kit on it that slp makes. once that is done you will want to get the primary clutch balanced. that is all that a friend of mine has done and he has 8,000 miles on his and it still runs strong. the 900 does vibrate and to some it is a huge issue to me its not as bad as my old arctic cat was. i love my 900 and would recomend it to a lot of people. every manufacturer has its cons and everyone has an opinion so this is just my two cents.
joe
