I saw these while googling for something else on Saturday, and just had to give them a try. I love DC cartos, but hate polyfill, so I drip and run high voltages instead. I'd been wondering what a DC atty would be like, and now I know.
Holy crap! I just opened the envelope an hour ago, blew out a tiny bit of primer (not even enough to soak a paper towel, nice), and put in about 12 drops. This thing is insane. It works beautifully anywhere from 3v to 7.4v, holds an incredible amount of fluid for an atty, doesn't leak, and stands above my 306/510's. I'm usually a cheapskate about buying atties, but this is definitely worth it if it holds out a month or two. I'm gonna OD on joy from using this at 4.5v.