Those e-cigs deliver nicotine without any additives other than nicotine and (I believe) something called glycexxxxx? which the nicotine is mixed with.
They (allegedly) are "healthier" than regular cigarettes in that those pesky tars, etc are missing, and since they are vaporizers, there is no second hand smoke, or odor emanating from them.
I have a couple, and do use them on occasion.
Whether they will actually help me to quit entirely will be something to wait and see. I do know I've not had much success quitting cold turkey, or with the patch.
They definitely help me go longer periods without a real cigarette burning, so I do consider it a smoking cessation aid, and cigarette substitute.