OK, I know this isn't the answer for everyone, but this is what really hooked me.  I started out buying Lucky Slicks Retro Mini e-cig.  It was good, but I still had to have a pack of analogs with me because my frequency of use put the bat life at about 2 hours.  As soon as one bat was done charging, the other died.  No big deal unless I actually wanted to have a life.  I did some research and tried a few products out "in mall" but nothing stood out, Until I found totallywicked.  I bought a screwdriver mk2, and it came with a total of 4 attys - 2 901, 2 510 with converter.  2 batteries that I get at LEAST 12 hours out of.  And a 10ml bottle of juice.  Yeah, its bigger than an analog, yeah it looks a little odd, but that was the point - I don't wanna smoke or look like I am.  The tornado is also an awesome product.  Now I haven't had a cig in 2 weeks and the last time I tried one it felt horrible.