While AT&T is now one of three companies offering the latest iPhone they were very pleased with the 'extraordinary demand' from customers to use the iPhone on their network.
Previously the iPhone 4 surpassed the reservations of the iPhone 3GS by a factor of 10 which caused AT&T servers to strain under the pressure, so we hope AT&T is ready for their new customers this time
AT&T also stressed on the fact that their HSPA+ speeds surpass the 3G speeds on their competitors and their network was the only once which allowed customers to talk while using the data connection. AT&T previously marketed their HSPA+ as 4G which makes AT&T the only company (due to a technicality) to offer the the iPhone 4S with 4G.