I go until I feel I've had enough. It may take more than ten drags off of a PV to get the equivilant nicotine.
This is the key, really - well, this and what hypothesis the experiment was testing. If the hypothesis was "puff-for-puff, e-cigs don't deliver like analogs", well, duh.
But then, my innate cynical nature must also question the rational behind the hypothesis... i.e. perhaps was it "How can I frame an experiment that puts e-cigs in a bad light?" I really can't see any other reason for conducting such a rather pointless experiment. But like I say, I have a cynical nature. Maybe Eissenberg was indeed just curious about the effacacy of the delivery system... but then why not use a less subjective methodology (i.e. why not use mechanical "puffers" and gmsc analysis or something like that)?
Anywho, in terms of actual use, however, yes it's obvious that we vapers tend to take more puffs (or a higher concentration of nicotine in the juice - I read the parameters and thought, "19 mikes per mil? That's for wimps!!") for a user to get "enough"... but so what? We are very well attuned to what is "enough", and will automatically get there.
And probably have more FUN getting there! After all, what makes e-cigs superior, at least to me, as a method of foregoing traditional cigs is the extra,
non-nicotine-related aspects of smoking: Having something to handle and fiddle with, inhaling and blowing stuff, socializing with other smokers, etc. etc. That's why I deliberately stick to my former schedule of going on "smoke breaks" with the other smokers at work, perform the perp-walk out to the smoking area, sit around and chat, and so forth - these aspects of smoking are at least as important as pure nicotine uptake.
And e-cigs/PVs do this like no patch or inhaler or gum can, plain and simple truth.
-Inspector 2211