They also suggest that because e-cigarette manufacturers are not required to submit clinical study data to them, the public has no way of knowing "whether e-cigarettes are safe for their intended use, what types or concentrations of potentially harmful chemicals are found in these products, or how much nicotine they are inhaling when they use these products." The FDA is also concerned that the marketing efforts of e-cigarettes may increase addiction to nicotine, especially in young people, encouraging them to experiment with real tobacco products.
Case in point, I work in a hospital and a fellow nurse smokes them right there in the nursing station. In addition, when participants smoked Eclipse, the nicotine concentrations in their blood remained fairly stable and their desire to quit altogether remained intact. Here's what current research says about the positive aspects of this product: