The reasons that I feel that the pleated paper is better than the UAT (and I have used both) are multiple: A) When I use the pleater paper, I mount it in a 20 or 24 oz. (Dubro, I think?) tank on a very thin walled Tygon tube with it weighted. It also then acts as a clunk and if there is an air leak or some other reason that air enters the hopper tank, you have a larger margin because the pleated paper also uses surface tension (as the UAT) but also follows the fuel around. B) its WAY cheaper! C) it allows me to use the 20 or 24 oz capacity of the hopper tank for a bit extra fuel volume D) no hassles of getting rid of bubbles.

That said, there are situations where a UAT is preferrable such as my Boomer Sprint where there really is no convenient spot for a 20 oz tank. I would have then made my own header, such as the MAP one (a small Nalgene bottle with a pleated paper filter in the middle, held rigidly), but I found a UAT laying around (I'm lazy!).