I think 3G is faster than EDGE. That's what a lot of the complaints were about on iPhone v1.0 , how slow the EDGE network is. I know my phone is faster on the web when it's on the 3G network than it is when on the EDGE network.
EDGE is the old and slow network--3G is the newer, faster network. I've got AT&T now after switching from Verizon in February. Was with Verizon over 10 years. Verizon has better coverage than AT&T IMO...may switch back. YJ.