I've got a RTV 500 Camo and I really like it. The hydro tranny does take getting used to, most guys pull up to a hill and as their speed starts to drop they plant their right foot.....with the hydro tranny you need to let off the pedal and you will get back into the power. If you aren't used to it that will drive you nuts the first couple trips. The ride is rough, kinda goes with being a work horse. The fuel economy is incredible, I have no idea in mpg what it gets but it has to be over 100 mpg, it uses next to nothing.
The advantages as I see them are the hydro tranny = no belt to slip, the Kubota is overbuilt.....I've pulled my 2500+ lb bass boat around the yard with no problems what so ever. Another big plus is that when you let off the go pedal the machine automatically starts slowing down and uses the engine to brake, if you're going down a hill and let off the accelerator your machine will slow down as well....brakes on this unit will last forever. I also like the fuel injected 2 cylinder engine, it runs so smooth and quiet you almost forget it's an offroad buggy. I also like the front and rear 2" receiver hitches, you can hook up ball mounts, shackle hitches, carry alls......with no problems because 2" is universal.
I've used my RTV 500 to do all kinds of work and it's loving it, I used it with a brush grubber to pull out small stumps from 2-4" trees I cut down, hauled trailers, mulch, and even my beagle when we went out chasing rabbits and I've yet to be let down by it. I can't say a Mule isn't great but it wasn't my first choice for the reasons mentioned. Enjoy which every you choose, I'm sure they are both fine machines.:thumbsup: