Can't wait to get mine out there. The last sled I rode was an 08. Apparently theres a big improvement.
Later.....
I was in s similar situation; the last sled I owned was an 03 Mtn Viper with a 144 "long track". The responsiveness of these new machines is very impressive. I'm happy I went with a new summit after riding my brother and sister's 17 RMKs. I do like how the RMK sets an edge but for me the crisp throttle and power of the 850 make it better than the RMK. I plan to lock out my tmotion and might end up centering my skis to see if I can make mine set that edge.