At least on AT&T it's only supported in a handful of random town in the middle of nowhere. Not only does it not work in NYC, there aren't even plans to get it working any time soon. By the time it's actually up and running with a reasonable amount of coverage the iPhone 6 will be out.
Right, Verizon is the "good" choice for the iPhone 5 (it supports GSM too when roaming), and Sprint is the unlimited (but slower, since LTE isn't rolled out yet) choice.
I'm going Verizon since they have better coverage in Yosemite and some other areas where no other network seems to have coverage.
At least on AT&T it's only supported in a handful of random town in the middle of nowhere. Not only does it not work in NYC, there aren't even plans to get it working any time soon. By the time it's actually up and running with a reasonable amount of coverage the iPhone 6 will be out.