Honestly, I tried them thinking 'I'll see what this is like', and wasn't very determined I was going to quit, and after a couple of weeks of not smoking real fags it kind of started to dawn on me that I could actually keep it up. I was amazed myself.
To Rizzy: it's not quite like smoking, and it all depends on nicotine levels and flavours etc. but you can't go wrong giving it a shot. An initial outlay of 30-35 quid. That's 100 fags. And if you want to you can stick with the nicotine, of taper down over a year. Or two. Or start smoking lime and chewing gum flavours.