I chose to go with K&n for a couple reasons. It is easier to clean and re-oil. With the uni filter the oil is very tacky and collects dust much faster. With the k&n (with the outer filter installed) it seems to not collect as much dust due to the pre filter doing its job so I like that I dont have to clean it as often. I have owned both btw. Also if you get the k&n recharger kit you dont have to mash the oil into your filter to get it all soaked in. Just spray the cleaner on, wait a few minutes, wash from inside out, let it dry, and then spray the new oil on it. Either filter is a good choice. And as others have posted an oiled filter will help with keeping water out a little better and is able to be dried out on the trail...
2018 Sportsman 850 SP Camouflage
2014 Sportsman 90 Sage Green
2018 Honda 250 Recon