Glorfindel has it right. In my experience the pleated paper works better than the UAT plus you can choose the size tank (I use it for extra capacity at the end of a flight. I know that if near the end of the flight my main tank might be bone dry so I still may have 20 or 24 oz left in the header. As long as I don't go wild on the aerobatics - which I would not cause I'm just trying to land at that point - I have that header reserve) plus I don't have to undergo any complicated hijynx to purge it (just tilt the airframe a bitwhile fueling to allow every single bubble out) plus it don't cost me $60!

Don't get me wrong, BVM stuff is for the most part the best stuff out there! But for a few bucks I can put something in my plane that, in my experience, is more reliable AND more user friendly.