The Ego or maybe, just maybe, the kr808 and l88r.
I only say that because its the normal "gas station"
ecig I see around here and if they have enough of those out there it probably outsells an internet only Ego (and its clones).
I would love to find some numbers from china, Blu has probably sold more units than every U.S.
mod maker combined has ever made, they report having 10,000 retail locations, even if each location just sold 2 it would probably out number ever SB, GG, Provari, Darwin, GLV, Reo, and Buzz sold.
Doesn't make them great to use just popular.