The only problem I see with the provape is the size,
its very close to the size of a GGTB and a Puresmoker Prodigy,
The GGTB can use the 14500 but it can also use the 17670 (the aw 17670's anyway) and allows for more choices in range
One of the best features of the 14500 is that it is such a small battery it allows you to use much smaller devices than any of the above mentioned mods, a 14500 box mod is really a small little mod, so is the icon (which only uses unprotected 14500's I believe)
From what I understand the provape is so big because of its safety features...however I don't know of any catastrophic single 14500 failures...especially if your using protected ones it seems a bit overkill to me. That being said obviously there are some provape fans
But for me the beauty of the 14500 is partially eliminated by the provapes (and the GGTB as a 14500 device for that matter) size...and partially by its price as the 14500 is also a cheap little battery and I like the fact that you can get a box mod a charger and two batteries for less than 40 bucks.