I have one 13 800 Pro rmk which has been used as a rental. It has over 6000 miles on it. In the course of it's life the belt drive has cost me more down time than any other part of this sled. It has gone through 4 jackshafts. Thanks to members of snowest forums, this problem has been fully resolved. Makes sure that all components are changed by your dealer if you have this failure, jackshaft, both bearings, and brake rotor, new bolts, washer and torque to 45# with new bolts with fresh Loctite. I have had two of the lower bolts break on the lower drive shaft. Easy out the bolts and replace, not a big procedure, but still down time, and had to be pulled out on the rope. For most people the quick drive is tolerable, but if you are someone that reliability is critical to you, go with the chain case. I only had the belts fail due to my jackshaft problems. This years quick drive belt has run 2500 miles with no failures.