ok, well, if you want to be pedantic and persnickety
'Vapor' is a noun - 'vape' is the new verb which has been coined to describe what one does
with the vapor.
When we puff on a PV we don't say we're 'vaporing' - we say we're 'vaping'.
so ... i vape, you vape, he/she/it vapes - thus one who vapes, is therefore correctly called a "vaper". (not a 'vaporer')
and further, although it could also be technically correct to use the existing verb "vaporize"... as in, to say
"I'm vaporizing" when i puff -- the problem with that is then we would have to call one who vaporizes, a "vaporizer."

- and that word of course, denotes something ENTIRELY different.

LOL