I've used them, and love them! I haven't quit yet, but only for lack of "want" right now. I know the moment will strike when I just *know* it's time.
I used them when I was in the hospital twice in November. I made sure I showed all the nurses and aides, so that if they came in while I was using it they would know what it was. It worked great for satifying those worst cravings, like right after a meal, or after waking up. And no, there is no odor. I blew the water vapor directly into the face of a non-smoker (at their request) and they could not smell anything. As a matter of fact, when word got around the employee's desk, many of them stopped by to ask about them, either for themselves or a loved one. One of the doctors even wrote down information about the e-cig to recommend to his other patients.
Yes, it is a nicotine replacement system, but you can wean that down to 0% as well. the cartridges come in different strengths, so you can go down to just flavored with no nicotine, for those who just like the act of smoking.
I highly recommend them. If you want, I know of a terrific company with great customer service. Don't know if I can post the name here, but you can pm me if you want for the name.
Good luck!
Oh, one more thing, don't buy the ones at the mall kiosk. From what I've read they're overpriced and don't work very well.
This is a great site with a lot of great information:
http://www.e-cigarette-forum.com/forum/
(hope the link is allowed)