AT&T Claims Fastest LTE Networks Speed in Third Party Study
T-Mobile doesn’t offer 4G, but its non-LTE speeds are the best of the group at 7.3Mbps down and 1.5Mbps up; AT&T is a strong second in that category, actually, with 4.3Mbps and 1.1Mbps.

A few of AT&T's 4G devices
Verizon has been the frontrunner in terms of rolling out 4G LTE networks, which it has done at a blistering pace. For instance, RootMetrics found Verizon’s LTE network in all 77 markets that they tested, whereas AT&T was only in 47. That number has changed, however, as AT&T said that it has now launched LTE networks in 26 of those markets, bringing its total in the tested areas to 73.

4G LTE coverage map (L to R: AT&T, Sprint, Verizon)
It’s clear that AT&T currently has the faster service, but the company has a long way to go to match Verizon’s coverage footprint--Verizon still holds the lead nationwide with 475 markets to AT&T’s 153--but once AT&T eventually catches up, Verizon will have extremely stiff competition. Sprint and T-Mobile should be sweating it right about now.