I just ran the FCC broadband speed app on my iPad 2 using the built-in Verizon 3G, and then ran the same app on my iPhone 3G, which is on the AT&T network. Verizon gave 1.04mbs & .84mbs in download and .6mbs in two test runs. AT&T clocked in at .19mbs & .61mbs download and .06mbs upload. More surprising was the speed using the Starbucks wifi network. It only gave .94mbs download but delivered 1.16mbs up.
Pretty interesting that Verizon is competitive with crowded in store wifi…