Vaporization of juice is better on your lungs compared to inhaling smoke and tar. Less to get clogged. Nicotine itself has been shown to be significantly less addictive combared to Tobacco. Theories for this typically involve the fact that there's more than just nicotine in tobacco. There's a chemical in tobacco smoke, the name escapes me at the moment, that acts as an MAOI, reinforcing the effects of nicotine.

This isn't to say that nicotine is harmless. Rather that the consumption of nicotine via vaporization is Less Harmful compared to smoking tobacco.