Live in Northern NJ.
Worked in midtown and downtown NYC.
AT&T is terrible. Massive dropped calls, calls that don't even dial out, data that does not work even though it shows 3G reception. When I'm in Manhattan, the GPS barely even works.
Now, it could be the iPhone4 that is the culprit. But either way, it's either AT&T or the iPhone4 that is garbage. And at the end of the day, I have an iphone4 that does not work well at all.
Funny thing is when I go out into the boonies, the coverage and data are flawless. Could very well just be that the northern NJ and Manhattan area is disgustingly congested that the service is garbage.