My concern is with the "pull" you take...When you suck on a real cig you lungs open up in a certain way,the smoke gets into areas due to the way you smoke,lung cancer enjoys this method...with a restricted pull or less...that unusual not recognised historical way of putting smoke or substance into the lungs may in fact cause harm...Is a strange idea i have lol.This idea to comes from my experiance with ready made cigs to hand rolled make ya own, with the tiped/filtered ready mades i used to cough up disgusting phelm in the mornings, roll ups made by me with out a filter and using a roach, no coughing,and no minging phelm at all...so from that experiance, i would guess the restricted flow of smoke from a ready made makes you draw the smoke in such a way that you get a build up of phelm in your throat...no filter and the draw you take is less and even though unfiltered would sound worse i beleive it can in fact mean you inhale smoke more so like we have for 100`s of thousands of years...not artificaly by restricting the smoke in some way and makeing the body change the way it works when enhaling smoke....blablabla...thats my wild take on it.
The "electronic cigarette" technology is too new to have any reliable long term data on which to base a meaningful assessment of relative safety.
However, it is reasonable to ASSUME that the electronic cigarette is safer, because it does not expose you to the same smoke-borne carcinogenic substances that are known to harm you, when smoking real cigarettes.
I don't have an in-depth answer, but I can tell you that e-cigarettes are formed with water vapor, which is not harmful. It will not leave residue tar in your lungs like real cigarettes will, but as mentioned above, there are no long term studies to prove if there are other harmful agents.
From what I have read, eCigarettes are not safe, but are safer as they do not have the tars that even filtered cigarettes have. They still do have nicotine though.