Average download speed, EV-DO Rev. A: 701kbps
Median download speed, EV-DO Rev. A: 440kbps
Average upload speed, EV-DO Rev. A: 322kbps
Median upload speed, EV-DO Rev. A: 286kbps
Average download speed: 933kbps
Median download speed: 840kbps
Average upload speed: 180kbps
Median upload speed: 215kbps
Unexpectedly, AT&T on average is 33% faster then Verizon when downloading data. This is quite a significant speed advantage; however, if you look at upload speeds you will notice that Verizon performs 79% faster then AT&T.
For those who spend a lot of time browsing online then AT&T clearly wins out. For those who upload a lot of pictures and video perhaps Verizon would be a better choice.
BoyGenius has a more detailed breakdown of the stats which can be found at the link below.