AT&T was giving us a royal screwing for years, as I had their "ultimate" package, but only getting about 1.5MB down after checking it at http://www.speakeasy.net/speedtest/. I discovered it when I signed up for GBTV and the download was too slow. Caused me to look for something better; cut my costs in half and service now is 10 times faster!
We'll see on the powerline device. Past experience hasn't been too great, but maybe they're more reliable now. I need it for a home automation project. The device I'm using only has hardwire capabilities.