*GLADLY* jump to WiFi because of AT&T craptastic 3G/4G service and infrastructure.

You don't realize how bad it is until you deal with a customer that had GUARANTEED SLAs (15min/year downtime) with AT&T only to be told... (effectively) we are working on something more important, who cares about you effin 20Mbps services we have other more important stuff to worry over.

Yeah, AT&T is way more of the issue that has trained iPhone users to jump in WiFi as soon as possible. A more reliable infrastructure would not have seen this shift.