Everyone has a different opinion here, so I cannot speak for all, but I can say based on my experience. The larger, more aggressive tires on my XUV get more traction than do the stock tires, by a fair amount. I love them in mud and the winter snow. I like them less in the summer when I am doing a lot of riding on pavement and less work where traction is imperative. A larger circumference tire on your XUV will lug the engine when climbing steep hills or long grades. If you live where it is flat or where the grades are short, this fact might not matter much to you. It did to me. More aggressive tread will definitely help traction, but unless you are running in deep mud or snow or bad terrain often, I do not personally think it is worth changing from the factory tread. The traction might be better, but the ride most likely will not. Despite opinions to the contrary, the stock tires get pretty good traction and ride better than most aftermarket brands. If you find an aftermarket tread that rides and wears as well, it probably will not get enough better traction to merit a change. My dealer, who helped me customize my Gator, frequently puts aftermarket wheels on the machines when he builds them up. Unless someone wants aggressive and oversized, he replaces the wheels but mounts the stock tires as he says he has found no aftermarket tire that offers any better combination of ride and traction for most buyers.
John M