I have never owned a UTV so I can not make a comparison.
As far as an ATV: We have had an ATV (right now a Yamaha Grizzly) for the past 15 years, used for snow plowing, wood and hay hauling, manure spreading, riding fences and every day farm chores. For our purposes and used several times every single day, it has been an excellent workhorse and I would not hesitate to get another one.
Personally, I prefer to be out in the elements, not closed up in a box with a steering wheel. I like to swing my leg over the machine instead of sliding in on a seat with a backrest. That's just me. No need for one of them fancy UTVs.
I would get some feedback from people who have owned both for the specific type of work you're talking about. Then go to a dealer and test drive both types.
Good luck and if you need more info you can PM me.