I do not own one, but the contractor, farmer, businessman that built my house swears by his. He had an older one not sure how old, he sold it and bought a new just a few years ago. He has cattle and does a lot of stuff with the Mule on the farm, His new one has the gas engine.
In the future I am going to buy a side by side, it will be mostly for work on my farm and home property. I don't care about those that haul butt and slide sideways at 50 MPH, I want one that will take the abuse that I give it when hauling wood or working on the farm. I have looked at the Mules in the past and also compared those to the Honda side by sides. I want one that I can gear down and not run away with me going down a steep hill, yelp I am in the mountains no flatland stuff around here.
Other than that I wished I could help you more.