I actually wonder if it's the 3G service compatibility. When I turn off 3G and switch to Edge, my call quality is stellar. This leads me to believe it's not necessarily the phone, but maybe an issue with the phone and 3G together? I have to be honest, AT&T's 3G is fast, when you can use it. And I have not heard of AT&T Blackberry users having the same problems.

However, I'm married to my iPhone, so I just put up with it.