The pumpkin adds 40 pounds over the 500, is a 4-stroke so maintenance is A LOT more expensive, and has a hydrolic clutch (which I hate). With that said, if I were opting for a bike to use on the road as a driver more than the dirt, I would stay with a 4-stroke because of the fuel (no mixing). However, for the dirt, not a chance. A lot of folks I know who were caught up in the 4-stroke craze have returned to 2-strokes, most because of maintenance issues.
Rick