We are pleased the AT&T iPhone monopoly is over (three and a half years later?!), but we do not expect that Verizon will aggressively pursue multinational enterprise (MNC) customers who frequently travel overseas with its soon-to-launch (data pricing not yet announced) iPhone service. The Verizon iPhone 4 will run on its existing EVDO network, so international roaming capabilities are limited since the CDMA-based cellular network platform is incompatible with the GSM-based networks used by well over 85% of the world’s cellular carriers. Verizon's iPhone won't work in cellular mode in most places outside the US and Canada. There's no such thing (yet — or likely on the drawing table) as a CDMA/GSM World iPhone, so the opportunity for your overseas iPhone travelers will be restricted to AT&T's network if your primary cellular service was purchased in the US (It should work okay in Wi-Fi mode for data, which helps somewhat.)
A second reason that enterprise iPhone users won't jump to Verizon is that they typically are bound by multiyear contracts (two years is the norm) – whether or not they are CLU (corporate liable user), and we anticipate that AT&T will play an aggressive retention game for North America-only enterprise iPhone customers.