I have snowmobiles and a 4WD ATV.
In "dry snow" where the tires can press thru to the ground, my ATV (4WD) goes great. If the snow is wet, or, heavy, or there is ice under it, all it does is make four polished round cradles in the snow where it sits. And it's not easy to get it out of those polished ice cradles. Sometimes I ride the road with my snowmobile, which packs it some, then I use the ATV on that packed trail. Sometimes the ATV goes fine on the packed snow (in the morning when cold) then in the afternoon it has trouble climbing even a slight grade or controlling direction on a downhill.
Snowmobile is good for a few months of the year. If you can ride from your house, great. If you have to "trailer" to the riding area, well you'd better WANT to do this.
I have a $1,000 Arctic cat snowmobile that starts with a lazy pull, turns around on a wide one-lane road. It never gave the tiniest bit of trouble. It starts every season and I haven't paid the least attention to "the gas", just get a can of starting fluid, and a few pulls on the rope and it purrs.
I also have a 150HP fuel injected 'mountain sled' that is 11 feet long, has 2 1/4" paddles, you have to stand off to the side and pull hard to start it. To turn around on a 1-lane road you have to go off the road. Or get off and drag the back around by hand. It weighs 450 lbs. I like it though, I'm just trying to convince you to try a small low cost sled if you want to get into this.
I'd have a hard time advising one for 4 seasons although the UTV will be usable for many more months including some snowy conditions.