*raises hand* I'm a nonsmoker who vapes, sometimes 0 nic, sometimes 6-18mg levels, depending on my mood and flavor availability. I started for the same reason anybody starts anything potentially unhealthy-- donughts, pina coladas, extreme sports, etc-- it seemed fun. And I enjoy it. I did a lot of reseach and concluded that the risk is probably pretty minimal, even if nicotine is involved (though this is a very individual judgment call). I've noticed no ill effects, aside from an occasional irritating cough, no worse than hay fever.
For myself, I think the ANTZ "gateway drug" theory is just silly. Near as I can tell, vaping is more enjoyable than smoking. The nicotine delivery isn't as efficient, but most people don't start smoking because they want to add nicotine to their lives-- they start smoking because they're curious, it seems cool, and it is fun. The nicotine gets them addicted and keeps them smoking against their better judgment. So the idea that tech-loving kids would start using a snazzy, flavorful electronic gadget and then switch to a cancer causing stick of burning leaves is kind of absurd.
And I'm not going to let the opinions of zealots, of any stripe, control my life. At this point in my life, I have plenty of practice ignoring the ill-informed opinions of a rabidly paranoid minority. I live my life the way that makes the most sense for me, and for the people around me. I don't have the time or energy to worry about what crazy people will think about my decisions.
After a few months of vaping 3ml daily or so, I can definitely say I'm not addicted. In circumstances where I've needed to go days or a week without vaping, it was a complete non-issue. Like reading trashy novels, or drinking a starbucks latte, it's a habit I enjoy, but can take or leave.
So do what seems best for you, in your life. That's the only standard that makes any sense, really.