The iPhone 5s is here, along with the new Touch ID fingerprint ID sensor, Apple A7 processor, M7 motion coprocessor, much improved iSight camera, and more LTE data support than ever. The best phone in the world is only as good as the carrier it's connected to, however, so for the last few days I've been testing it on AT&T in the U.S., and in several categories including call clarity, data speeds, tethering capabilities, and more. Does the updated LTE support that Apple is calling UltraFast really make a difference on AT&T? Are their any improvements over last year's iPhone 5, and if so, are they substantial? Let's find out!