Fastest 3G network?
Well, that's hard to say. I said it before, but AT&T's 3G experience is like driving a Ferrari with some prick in the front passenger seat yanking the parking brake every 90 seconds.
Simultaneous voice and data?
Well, that's only good if you've got good 3G service in your area. If you're going into a dead zone, you'll no doubt get simultaneous voice and data outage. If you're going into EDGE, which they have a lot more of, well, no simultaneous for you.
Most popular smartphones?
I'll give them that, considering both GSM is more prevalent around the world to give more wireless device manufacturers the abillity to provide for the US, and that Verizon's lineup has always been third-rate at best.
Access to over 100,000 apps?
Not your call. Considering that it's Apple's iPhone and their iTunes store that provides that, AT&T is barely making the argument work, only until their exclusivity ends. Add the fact that the iPhone is not even mentioned in the ad, just some other smartphones, that bullet point shouldn't even be mentioned.
AT&T rested on their laurels and their profits with the introduction of the iPhone. Perhaps if it was still Cingular, we'd be in a different scenario by now. But, AT&T remains greedy, from doing things like raising cost of data plan for iPhone 3G users by $10 AND removing text messaging into a separate plan, to screwing over their own salespeople by intentionally ordering a fraction of the iPhone inventory - even as an exclusive US carrier, mind you - just so Apple employees can sell more of them without getting commission.
They get what they deserve in this round of ad wars, and their rebuttal was pathetic at best, though it will serve a moderate portion of the uneducated and unsuspecting public, unlike you and me here on sites like this.