My partner for one.
All E-cigs are not created equal. Not all have nicotine - my partner used ones that were nicotine free - just flavoured. It was more for something to do - which is half the problem with quitting - you smoke at times you are doing something specific like talking on the phone, etc.
I'm not smoker, nor have I ever been (excuse: my mother (even aged 30) is too scary!hahahaha), so I don't know what it's like to give up - but I think we should support them and whatever method is their choice, rather than dump on them.
Support helps to quit, not condemnation