It's a potentially strong start to one of the few truly cross-network mobile payment systems in the US, but we see a long road ahead before Isis gives Google Wallet some jitters -- there's legions of banks, cities and stores needed before Isis is widespread, and we're not counting on that ever-elusive universal hardware support.

ENGADGET: Isis' NFC payments go live in Austin and Salt Lake City: 3 carriers, 9 phones, 1 long way to go (video)