I use both. Usually what I have been doing is condom refill on first fill. I actually purposely overfill it to get it nice and saturated, then blow out the inner tube, clean off and let sit for at least 10 mins, if not longer. Then I toss the condom or if its a good condom put with cartos and drip tips that I am cleaning later in a baggie. Then I drip refill for the rest of the refills usually.
Lately tho sometimes I will use the condom refill method again after the first fill if I'm just at home and I really want my carto nice and saturated and flavored. It just doesn't get as saturated for me when I drip refill it. So to me, condom refill works better, I have a nicer stronger tasting carto, but drip refill is more convenient and less messy.