Coin Card Teardown
I had the beta and a final Coin and neither one were reliable enough to to trust. You HAVE to carry backup cards which more or less defeats the purpose. Then there is the slightly embarrassing, extremely annoying "Your card didn't work/Do you have another card this one isn't swiping". I've stopped carrying my coin altogether because if you have the cards you might as well use the real ones (I tried for 7+ months to use coin first).