I useor have used, on a regular basis, the Mule, Ranger, and RTV.
The RTV is nice, but it is heavy, rides rough, won't go as well as the others, and will only allow 1 passenger even though it has a bench seat.
The mule is a sweet machine but is not as durable as the Ranger. The mule will only go abot 25 mph, bt that is plenty fast most of the time. Since it is all steel, rust is an issue, as well as dents, and they both WILL happen.
The Ranger is a beast! Since it is plastic, limbs and rocks just bounce off. Our RTV is almost new but looks like heck because of dents and scratches just from binding things down in the bed. This was an issue with our Mule too. The Ranger goes faster (50+ mph), rides smoother, goes better, (Rangers will go where others, 'cept maybe the Rhino, won't even think about going) and will haul 2 passengers (3 people in cab. I have had both my kids & m wife w/me before). The Ranger's bed is a bit smaller than the mule or RTV but it hasn't been a problem. We use our Ranger almost every day on the farm and hunting, if I couldn't have it, I would consider the Rhino or mule.