[jyl]

Easy call - switch over entirely to to VZ, they have iPhone and BB, better coverage, ahead of ATT in 4G/LTE deployment and 3G coverage. T-Mobile is going to be folded in ATT in time, no escape there. Sprint I'm not sure about.

A contra-argument would be if your wife has a grandfathered ATT unlimited data plan for her iPhone, but I don't know how long ATT will honor those and if it even matters for her usage?

Cellphone choices are very personal, because coverage is so variable. My ATT coverage has improved remarkably in the past year, and I get tolerable coverage to the places I travel (NYC, Boston, SF - all downtown) - but that doesn't do squat for you . . .

Another choice - more money but maximum coverage - would be to add a MiFi or similar cell/WiFi hotspot, if you can't get cell coverage on the phone you can get data coverage on the MiFi (being on a different carrier) and use Skype. I carry VZ MiFi and ATT iPhone when I travel, so that I can get coverage everywhere. Sucks to have to do it, but . . .