British researchers find that e-cig users have a 60% higher success rate in quitting than those who use smoking cessation products like patches or gum or willpower alone. In a five-year study of almost 6,000 smokers, almost 20% of those who switched to e-cigs stopped smoking conventional fags. Only ~10% of those using patches or gum managed to quit. Slightly more than 15% quit using their willpower.
The long-term effects of vaping are unknown at present but they appear to be less bad than tobacco.