The 1000 mah is very long. Add a Phoenix XL and a drip tip, and I feel like I should be shooting pool with it. I really like this battery, though. It's slimmer, and even a little shorter, than my iPro, and I had forgotten how good that rubbery coating feels in the hand. As for the advantage of having a VV device, I've somehow ended up with three of them and I still can't really answer that question. I find that I pretty much stay around 4 volts, mostly because I can't get out of the habit of buying low resistance cartos and attys. Under these circumstances, I probably would have been just as satisfied with the upgraded eGo C, as BGabe mentioned. Having said that, the VV is still kind of a nice thing to have, especially at this price point. If my usual low res cartos are out of stock, or the 3 ohm is on sale, I can be flexible. What I will do next time, though, is get the 650 mah. Judging by the vape time I'm getting on the 1000 (more than a day of moderately heavy vaping), I think the more portable 650 would easily get me through a day trip or a night out.