I don't smoke - I never have. I've personally considered taking up ecigs on several occasions.

I haven't done so because the ingredients in the fluid flavorings are so oddly unregulated - You end up with weird things which really aren't safe to be heated and inhaled.

If I had confidence that there was sufficient oversight, such that they were only moderately dangerous, not "close our eyes, and hope for the best", I'd likely start using the devices.