FWIW I know both of the researchers who are frequently cited for their research in e-cig safety, and they are emphatic that even though there are health risks with e-cigs they are absolutely vastly dwarfed by the known dangers of smoking real cigarettes.
According to my doctor, vaporizers are linked to cardiopulmonary disease, but with about 3% the incidence rate of cigarettes.
Well, there is so far exactly zero conclusive research indicating that, but there is some preliminary research indicating an increased risk of atherosclerosis. Nicotine itself is a pretty toxic substance (and not in a "ZOMG TOXINS!" way) so I wouldn't be surprised if there are some deleterious effects from vaping. Definitely still much better than cigarettes, though.
I would figure that we won't have conclusive information on the effects of vaporizers for at least a few decades, since they're still fairly new. Additionally, a lot of people using them have history of smoking, so linking vaping to cardiopulmonary disease is confounded by that.
So really, people of all types should vape it up, because we need DATA, damn it!