AT&T just ran out of Sept. 21 stock for the iPhone 5. The delivery page has now pushed sales to “14-21 business days,” which equals almost three to five weeks. Verizon ran out of stock earlier today, but it is hard to determine if this shows demand per carrier since AT&T is such a big legacy iPhone carrier and Apple obviously gave it a lot more stock than others.
Both big carriers have downsides: AT&T will not run FaceTime unless you buy a Mobile Share plan, while Verizon will run FaceTime on all of its iPhones—but new customers must sign up for a Mobile Share plan (no matter what). In addition, the CDMA version of the iPhone, which Verizon and Sprint both carry, will not support simultaneous talk and data. Speaking of Sprint, it is still advertising ship dates of Sept. 21.