The carriers usually give a wide range of expected data speeds with LTE, with AT&T saying its HSPA+ will be three or four times faster than 3G and LTE about 10 times faster than 3G. In general, the carriers say that LTE will give users more than 10Mbps on downloads, and from 1Mbps to 4 Mbps for uploads.

Another forum user on forums.imore.com, "Eviljack8," showed his AT&T LTE data speeds outside Atlanta were up to 20.1Mbps for downloads and more than 10Mbps on uploads. But a user in the Minneapolis area said, "AT&T still has some work to do in the Twin Cities." That user saw download speeds of just 3.2Mbps and upload speeds as high as 1.3Mbps.

By contrast, another forum user accessing the Rogers Canada network in Toronto, "MathieuLLF," provided a screenshot indicating a download speed of 57.09Mbps and an upload speed of 25.27Mbps -- far greater than any U.S. customer has experienced.

An editor for Computerworld in Framingham, Mass. along a major interstate highway where service is generally good reported up to 6.9Mbps on downloads and up to 8.47Mbps on uploads with his new Verizon iPhone 5.

The three major U.S. carriers all said LTE service has been normal since the iPhone 5's arrival. "Our customers can expect a great experience on the iPhone 5 on AT&T's 4G network, the nation's largest [with HSPA+ included], said AT&T spokesman Mark Siegel. "They can talk and surf at the same time and get blazing fast speeds."