two of the guys in my group have bought doo demo sleds from stojans in gp and they both have had great luck with them, the price was good and they are lightly but effeciently modded
i wouldnt see anything wrong with it. price is good with season creeping up. but saying it was ridden like a rental....how do you plan on riding it?? they are made to run the way they do to the bar and up. jump on the damn thing and ride like you stole it. like said compression test and youll be good to go. im sure that at demo rides they watch and make sure you warm them up, at least at the start. but if you were to buy off kijiji, well there goes the peice if mind that the dealer would even warrenty it. they must trust it. kijiji is so easy to find lemon's. JMO
Like I said earlier, my biggest worry is that there was no break in. Don't know how I could tell. This is my first sled, I don't know much about them, don't know if the dealer will tell me what I want to hear or the truth..
I know several guys that have bought demo sleds, they've all had good luck with them. keep in mind that there are many guys on here that can tell you stories of their brand new sleds blowing up and breaking down so its being a demo isn't that good of an indication of its reliability.
I bought an M8 demo sled and rode it for 3 years with no issues. If the sled was coming from a reputable dealer with full warranty I wouldn't be worried at all.