[atrettel]

Yeah, getting quarters is a real problem, especially when all of the banks in your area are only open during business hours and not on weekends. That said, I'd personally prefer quarters over an app, since quarters are much more fail-safe. The system that I'd prefer overall though would be some kind of prepaid account and an NFC card. UCLA had this system when I was a grad student there and it was really easy to use. You just tap your card on the reader by the door and select what machine to use. Everything ran smoothly.