I would love to have a UTV or ATV, but I am willing to bet that the work that is typical for my place would still prompt me to get the old 8N tractor and small farm trailer out over a UTV. I would get the most use out of the modern vehicles when it comes to pleasure drives around the old 40 acre farm and occasional hunting.
And, as RAH mentions...The cost is nutty. If it came with a farm hand, I think I could justify that!
My neighbor has cattle and his UTV is invaluable, so I see the benefits, but my needs revolve around some fire wood, brush clearing, & rock relocating. UTV's would not do it like my old tractor and trailer.