Got one yesterday and I love it! I sold my dragonfly 1.2 since I found it too bright, and though I didn't get a chance to compare the two, I absolutely prefer the sound of the fulla since it lacks the glare that I experienced with the df. I was a bit worried about the build quality from what I'd read on head-fi, but I think it's totally fine, especially considering the price. And it's so freaking tiny, almost as small as the df.
I couldn't tell much difference in sound quality between the dragonfly 1.2 and fulla - spent some time switching back and forward between the two. I liked the analogue volume control on the fulla, and the fact that it could drive my headphones really really loud. If I'd known about the fulla when I bought my Dragonfly I would have probably gone with that, but not for sound quality reasons.
I think I prefer the fact that the fulla completely disables all computer output controls. I know the Dragonfly uses an analogue output attenuator, but a rotary pot just feels better in my mind.
edit: it makes the fulla better with the PS4 as the PS4 appears to have quite a low volume setting when you connect a USB audio device to it - the fulla I could crank when playing driveclub with my HD-555's and there was loads of headroom. The Dragonfly was at max and it was quite loud, but didn't have much volume range left.