CurrentC is a great example of a "for programmers, by programmers" product.
I take serious offence with that. The problem is (a) mad requirements from upper management what data they want collecting, and (b) the mad requirement that the NFC hardware and the standard software in each NFC terminal mustn't be used. Probably some mad requirements for hardware cost; bluetooth should have been capable of creating a less clumsy implementation.
The google store is doing just as well too.
https://play.google.com/store/apps/details?id=com.currentc
No surprise. So they managed to piss off all the iPhone users (there are few iPhone 6 owners now, but _everybody_ wants an iPhone 6), PLUS all the Android users. Keep going, people, there are some Windows Phone and Blackberry users that aren't annoyed yet!