Personally, I see this more of a global technology change than a 'AT&T is better than VZW'.
VZW does have LTE 'and' CDMA to cover the vast majority of the country
AT&T has GSM / UMTS / LTE to cover the majority of the country.
On a global scale - I suspect that GM is abandonning CDMA chipset completely for any new products. As VZW hasn't completed LTE, and GSM/UMTS is by far the largest footprint on the planet ( »www.4gamericas.org/index.cfm?fus···geid=565
) moving to an all GSM/UMTS/LTE based deployment does make sense - even if it happens to end up on AT&T.