Not sure if you meant AT&T DSL Extreme, since they offer a DSL Extreme product, but I have it. I've had the 6.0 mbps line for about 18 months and love it. I consistently move gigabytes of traffic through SSL tunnels at 5 mbps consistently, sometimes a bit faster. Overall, I'm very satisfied with what I get for $39 a month AI with a dry loop line. I had to call AT&T once when my line was a day late being activated, but since then it has worked excellent provided I reboot the modem every two weeks or so.

My only complaint is I can't get a standalone 18 mbps DSL line in my location.