My Dad uses one and gets on well with it (smoker for 50 odd years I guess) and he's not touched a proper ciggie since he switched over, and he saves a fortune. He uses
http://myepack.co.uk/ but there's plenty out there. From what I've read, plenty of people don't get on with the ones that look like ciggies but they do get on a lot better on the Mod style ones. It may take a bit of time to get the right flavour and strength liquid for you but a lot of sites do sample packs.