Different tech (2D barcode scanned at register) and an indirect form of payment (pre-loaded card potentially linked to a CC), but Starbucks did just add nationa

Different tech (2D barcode scanned at register) and an indirect form of payment (pre-loaded card potentially linked to a CC), but Starbucks did just add national support for payment via iPhone (http://reviews.cnet.com/8301-19512_7-20029001-233.html http://reviews.cnet.com/8301-19512_7-20029001-233.html). I'm curious, has anyone had experience (good or bad) with payment via mobile in Japan?