This article is from PC World :
AT&T says it has worked hard to improve its much-maligned 3G network over the last eight months--erecting hundreds of new cell towers, using better-performing wireless spectrum, and souping up its cell sites across the country--and the results of our latest 13-city 3G network performance tests suggest that the network has indeed undergone a drastic makeover.
After registering the lowest average download speeds in our 3G performance tests last spring, AT&T’s network turned in download speeds that were 72 percent better than the numbers from eight months ago; in our latest tests, AT&T's download speeds were 67 percent faster on average than those of the other three largest U.S. wireless providers--Sprint, T-Mobile, and Verizon.
In our tests last spring, AT&T posted an average download speed of 812 kbps (kilobits per second) across 13 cities. In our tests conducted in December 2009 and January 2010, AT&T’s average download speed increased to 1410 kbps.
AT&T's download speeds in New York City were three times faster in our latest tests than in our tests last spring; in San Francisco, the AT&T's download speeds were 40 percent faster.
The AT&T network’s reliability improved dramatically, too: Last spring, PCWorld testers obtained a usable broadband connection with AT&T only 68 percent of the time. In our latest tests, testers connected to AT&T successfully in 94 percent of their attempts.
Check out the full article for more detailed results and charts.