[AT&T] has pretty consistently the fastest 3G network nationwide, followed closely—in downloads at least—by Verizon Wireless.

Specifically:

• Download test: AT&T, 6 for 12; Verizon, 4 for 12
• Upload test: AT&T, 12 for 12
• Tested metro areas: Atlanta, Chicago, Denver, Las Vegas, Los Angeles, Maui, New York, Phoenix, Portland, Seattle, San Francisco/Bay Area and Tampa.
• Participating: AT&T, Sprint, T-Mobile, Verizon
• Tested with stripped-down Acer Timeline laptops and 3G wireless modems from the telecos

This is speed only! Not tested:

• Dropped voice calls
• Customer service
• Map coverage