I still use 18mg juice, so I wouldn't use the word "quit," but I don't use traditional cigarettes anymore. I started with 24mg, and now use 18mg, but I vape more frequently, so I'm not entirely sure I cut back either.
The other night my wife and I were playing a board game and I was vaping fairly compulsively, almost like a pen chew, so I mixed my first batch of 0mg, and found myself perfectly satisfied by it, so take that for what it's worth. I still want to vape shortly after I wake up, with coffee, after I eat, etc.
My quality of life is a heck of a lot better, so other than a continued addiction, I'd say I have most of the benefits of quiting. The argument could be made that now I have less reason to quit because I found an alternative that isn't such a nuisance (hacking, smelling, having to go outside, whatever.) But the same is true of NRT products, and these are hailed as life-saving inventions. I'm not bashing NRT, it's great as a "replacement," but neither using NRT or using e-cigs is "quiting."
The only way to "quit" is to "quit." I have quit many times, and frankly if I had to figure out why I always come back it's because at some level I really do enjoy it. If I wanted to quit vaping, I'd do it the same I have quit cigs - I just stop (that makes it sound easy. It, of course isn't, easy but that's the only way to do it - just stop.)