Condom fill if it works for you, but looking at all the excess juice in the cap afterwords just made me cringe. I find myself disliking my new smoktech tank because of the juice that comes out of it when I'm refilling. Everyone's welcome to their personal preference though. Like with the tank I just mentioned, a few cents of juice wasted doesn't mean I'm going to spring for a much more expensive option with a side filling hole, it just irks me.