Electronic Cigarette are considered as a replacement for the cigarette but it us not perfectly true. The device produces the sensation of smoking to user but it does not exposes the user and the other close by to the harmfull levels of cancer causing agents and other dangerous chemicals normally associated with traditional tobacvo product.
They are nicotine delibery devices intended to be used like cigarette. But here queation arises that what will happen to some one who stops inhaling the tar of cigarette and inhales only nicotine.
We dont know that perfectly but there is definitely some of the side effects of it.
So for that I would rate it with 3stars.