How long do you want to keep it? Will you be using it as a utility vehicle or are you going to take it out on the trails?
I have owned a John Deere 855D Diesel Gator for 12 years. It's Yanmar diesel just sips diesel fuel. It has the electric dump bed. It has a centrifugal variable speed trans. It is 4WD. We like it, but it has some issues that I am not a fan of.
Things I like:
Diesel. Very fuel efficient. Low RPM torque. Less maintenance. If taken care of, twice the life of a gas engine.
Frame. Well built. Very rigid. Will carry 1000 lbs, no problem in the bed. Will pull up to 1500 Lbs.
Body Panels. Plastic. Withstands many bumps and bangs without denting or cracking.
Things I don't like:
Centrifugal variable speed trans: If you take the vehicle through water and water enters the belt housing, you will not go anywhere. Period. Until the belt dries out, you are not going anywhere. Ask me how I know......
Centrifugal clutch fingers: Have a tendency to get bent when pulling heavy loads that offer some ground resistance. I have replaced mine twice.
Electric Power Steering: The thing has thrown faults ever since I have owned it. Been in the shop at the dealership several times. They can't figure out what is causing it. They want $3000.00 to replace the control box, even though they don't know if that will fix it.
Electric/hydraulic dump bed: Works good, but is slow and draws lots of battery amperage when running.
Yanmar Diesel: Doesn't like cold starts in single digit temps.
No enclosed cab. Only a lexan windshield, which scratches very easily. It does have a ABS plastic roof. It rattles a lot when engine is running.
If you are looking at it as Utility use only and don't mind top speeds of 25-30 MPH, then Diesel is the way to go. If you want to go in speeds excess of 30 mph, then get a gas burner. I look for utility functions, low end torque, logical creature comforts and longevity. A gas burner UTV with a high reving, fuel thirsty, gas engine will get you on down the trail at speeds close to 50MPH and launch you into the air going over jumps. You can use it around the farm, but it wasn't really designed to be a utility vehicle. IMO, the gas burners are basically a jacked up, go-cart with doors for adults. If I want to go fast, I'll go jump in my Audi. A diesel engine will cost more, but with proper maintenance, it should last twice as long as a gas burner.
Best thing to do is figure out how you will use it the majority of the time. Make a list, then go to several dealerships and go for a test drive. Don't baby it, drive it like you just stole it.
Hopefully they have some area around the dealership where you can take it out, climb some hills, rough terrain, mud, etc. This will expose any issues you may not like. A gravel parking lot is not a test area. I repeat:
A gravel parking lot is not a test area. If they will only let you idle around a gravel parking lot, forget about e'm & go test drive someone else's vehicle.
Look at warranty. Who has the best. If you are going to finance it, some manufacturers are offering 0% interest for up to 36 months. Dealer support and network for getting repair parts. Is the pipeline available to get parts quickly? Does the dealership have a good reference from previous buyers?
On that note, I am getting ready to pull the trigger on a brand new Kubota RTV-X1100C UTV in the next couple of weeks. Larger Kubota diesel, all hydrostatic drive, hydraulic steering, hydraulic dump bed, remote hydraulics, full air tight cab, heat/AC, windshield wiper, blah, blah, blah. Out the door with all the options I want: Just over 28K. For a similar model from Deere: close to 40K. Deere still uses the same smaller Yanmar diesel engine and the same trans setup as my old JD 855D. The new models are geared towards the younger generation, who must have every over-priced gadget known to mankind inside the cab, so they have bragging rights out on the trail. After 12 years of running my Gator year around on my farm, in my woods and on the back country roads, in all kinds of weather and all kinds of terrain, none of those fancy bling gadgets will benefit me in any way or fashion.
Believe me, I am a Deere man through and through. All my tractors, farm implements, mowers, etc, etc are all Deere. Why am I switching to Kubota? Deere has just got too damn expensive for their own good and has overloaded the Gators with too many gadgets that just are not needed. I found a better product, with better warranty, better price and a well thought of supporting dealership. So, I am changing from Green to Orange (Camo). Still keeping the Gator, adding the Kubota to the ever growing fleet. It will give my John Deere sales guy something to cry about next time he comes out and visits. We have a long 25+ year business relationship......
). I probably actually just need to stop in the sheriffs office and ask them. I have seen someone on an UTV on the shoulder of the main Farm Road, we have lived here less than a month so still trying to figure things out. I am not a total noob, been on many dirt bikes, 4 wheelers, a few UTVs in my years, just a noob to tending to land, mending fences, etc. Was a kid last time I helped...