I do know that here in Atlanta AT&T has been making it very difficult for third-party ISPs to operate. With AT&T trying to hard to kick Comcast in the ass, they are now giving priority to AT&T's on demand video, I often get disconnected or get smacked with high latency at peak times. My neighbors who use AT&T's own dsl, don't have these issues.
I'm just waiting for the day when AT&T says enough and just boots them. I really don't know what I would do. Comcast filters, AT&T plays mean kid on the block lol. Besides, my third-party ISP actually has employees who answer the phone, speak english, live in the same town as me and KNOW WHAT THEY'RE TALKING ABOUT!!