We’re in for the next round of an ugly ad war involving Apple’s iPhone, America’s leading carriers and their definition of a fourth-generation cellular network.

Just as Verizon Wireless finally sealed the iPhone deal, T-Mobile USA was quick to point out in a new advert that this won’t change anything because iPhone folks, as they see it, are still doomed to slow network experience.

The 30-second commercial, embedded below, features two guys in suits who play Verizon and AT&T, an elegant black-clad dude representing an iPhone 4 and a sexy lady introduced as a T-Mobile myTouch 4G.

When the sexy lady asks the iPhone guy how he’s able to tell the two carriers apart and if one of them has "nationwide 4G like me," he responded:

Nope, I’m pretty much slow with either one.

The advert wraps up with the "America’s largest 4G network" tagline, despite the fact that T-Mobile’s network is 3.5G rather than a true fourth-generation network in an 4G LTE sense. It’s no coincidence, of course, that the setting and the overall execution of the commercial are reminiscent of Apple’s Mac vs PC advertising campaign.

The Bellevue, Washington-based carrier, a subsidiary of Deutsche Telekom AG, is the nation’s fourth largest wireless operator with nearly 40 million subscribers and annual revenue of $17 billion. Last November, Americans on T-Mobile USA experienced the widely reported outage which affected their ability to receive calls and send and receive text messages. The carrier attributed the service interruption at the time to "a backend system software error."