Charge Plug

And in terms of it failing? It seems to me that almost everyone I know with regular OTPs feels the need to start upgrading components soon after they get it. So there's some sense of an OTP not doing the trick there or this wouldn't be happening.

this isn't necessarily true, many OTP buyers enter the fixed/track world with little knowledge about parts. Once they start riding and getting more involved many of these people are drawn to 'bling' parts, replacing barely used components for one with much trendier logos.