UTV vs. ATV
I have 2 UTVs (RZR 800 and 660 Rhino) and Utility quads (Kodiak 450, Arctic Cat 150, Grizzly 125) and even a few sport quads (Raptor 250, and 2 DRRs). They each have their place. The UTV's are better for hunting, camping, and when you want to have a buddy along to talk to. UTVs are great when you have kids. The quad can go more places and seems a little safer because you can shift your body weight around.
Trails: My RZR can pretty much go where a larger ATV will go through the woods. The Rhino needs a little more room to make it between the trees. You can't take a Rhino down a tight woods trail. UTVs are tougher to make sharper turns between the trees. UTVs tend to high center over steep bumps (like dozer made roadblocks). Trail advantage goes to the ATV.
Fire Roads: The UTVs ride smoother and because of this, they can be driven as fast as a sport ATV on wider fireroads. You can blast over small washouts and rocks without slowing. Fire Road advantage goes to the UTV or sport quad.
Mud: My Rhino has a big tire clutch kit and has 27" ITP 589 mud tires on it. It can still get stuck because of the weight and inability to shift the weight around to look for traction like on a 4x4 Quad. The 4x4 UTVs will go through the mud better than a sport quad though. My stock Kodiak 450 will go through the mud better than my mud ready Rhino. Mud Advantage goes to the ATV
Fun: Both ATVs and UTVs are awesome fun! I've ridden quads for 30 years now and enjoy riding with my kids. We ride 4 to 5 days a week. UTVs are great for the kids that can't keep up with the rest of the pack - just strap them into the navigator's seat and tell them to hold on. My wife seems to like the RZR best because she takes my daughter along. I like the UTVs because you can share the experience with someone else. It's nice to be able to talk to the person next to you. It's sometimes fun to scare them too
The Fun advantage goes to the UTV - although its also nice to be alone on a quad at times.
If I could own one just one, I would have the UTV. A small narrow one like the RZR. I enjoy having a companion along to share the ride with the most.
2013 Apex 250f GNCC Edition
2013 Yamaha Grizzly 700
2011 Yamaha Raptor 125
2010 Yamaha YFZ 450X
2010 Yamaha Raptor 250
2009 Polaris RZR 800
2008 Yamaha Raptor 250 SE Custom