I work at a call center and was the first one here to give e-cigs a go, and I've been vaping since September 2009. There have been three other people who got interested in e-cigs after seeing me vaping and asking me about it. Out of those three, only one still vapes e-cigs regularly.
The first person, a guy, decided to give e-cigs a shot. He got a 510 kit and some of JC Original Smoke Juice. He is Arabic, and he said that the smoke juice tasted like some of the pipe tobacco he remembers from his childhood. But e-cigs have not replaced analogs for him. He said he will use e-cigs solely when he cannot smoke analogs, such as on an airplane or in a bar. When I asked him why e-cigs have not replaced analogs for him, his answer was: "the battery is killing me. I want a battery that lasts 24 hours." When I told him battery mods, he told me that he didn't want something as large as the Silver Bullet-mod that I use. He said it looks strange.
The second person, a girl, who no longer works here, also decided to give e-cigs a shot, but she also switched back to analogs, for another reason entirely. In a small town like this, you can't go to the store and buy a bottle of e-liquid or a spare atomizer. You have to have the money to invest to stock up on this stuff before you run into issues. So this girl had problems with that, she either ran out of the stuff and couldn't wait for it to arrive in the mail or she simply didn't want to wait for her payday to go out and buy 'in advance'.
I have also spoken to others who will not switch because they are devout Newport smokers and as anyone who has ever smoked a Newport knows, it's very difficult to replace with any other menthol cigarette, let alone a menthol e-liquid. Of course, just like anybody else, if a person wants to make the change to e-cigs, they need to be willing to give it a chance and realize that it's going to take some getting used to.
Anyway, this is what I have observed from others who have tried e-cigs and failed.