What do you mainly do?
I've ridin' an XP and seen M's strutt their feathers and both are impressive. I was amazed with the XP, I felt right at home on it, feels like an 2005-2002 Polaris EDGE that is really light, powerful and manuverable (did I spell that right). I ride an edge or a gen 2 and the XP blew me away. A guy I ride with got an 06' M7 162", rode it for 2 years, got an XP 154", rode it for 2 years, and is now selling the XP to get an M8. He likes the M's manuverability (did I spell that right), but hates the cap melting. He liked the XP's light wieght, power and most every thing in general. Twas it me, I would probably test both of them before I decide. This guy test rode the 09' M8 and has decided to sell the XP in the spring, so if the 09' M8 was better for him than the XP was, the 2010 M should suit him better. He is a taller than you, personally I'd get the M. The M is proven, the XP is a best seller, take your pick, you'll be happy with what you get. Being a Polaris man myself, I'd like to say "get a 2010 Dragon" but I don't know enough, Nytros and Apex with no boost are TERRIBLE (this I know, saw and expierenced).