According to Ookla, creators of Speedtest.net broadband test, AT&T network gives faster Internet to iPhones than the Verizon network.
Speedtest.net Mobile Speed Test is a popular app for the iPhones that calculates downloading and uploading speeds. According to it, average download speed of AT&T Phones was 1,769 kbps and the upload speed was 730 kbps. The download speed of Verizon phones was 848 kbps, while the upload speed was 506kbps.
So Speedtest.net says that AT&T Internet speed is roughly two times faster than the Verizon iPhones Internet. It has arrived to this conclusion after analyzing the data from 43,000 AT&T iPhones and 14,000 Verizone iPhones. But if you use your iPhone mostly to make calls Verizon is the better choice as it has broader network coverage.