If it's your first sled and your not that experienced, I wouldn't buy a 800-900cc snowmobile. A 600-700cc sled will probably have more than enough power for you + they are easier to throw around and are generally lighter (unless you have like 12 grand to spend on one of the new revs (they are BAD ASS). I have a 2006 Polaris RMK 700 159" track, and have never gotten into a situation where I needed more power, and its hill climbing and pow riding abilities are sick! People have mixed feelings on track sizes, my track is pretty huge, but it does great in powder (I kinda suck at snowmobiling, and the times that I do get stuck, I get REALLY stuck). Smaller tracks you will go faster, and easier to manuever (race ski compared to Pow ski ex.). All brands are generally good, there are definitely certain models you should stay away from, just google some and you will find reviews). Generally though, the ski doo revs, polaris rmks (except the last couple model years on the bigger engines) are sick. Not really sure about the Arctic Cats, but it seems everybody with the M7s and M8s love them. The new yamaha's are rad, especially the FX Nytro, the phazer is underpowered, the Apex Mountains are as sick as it gets....It all depends on how much you want to spend, used or new etc... my two cents