Yeah.... I have it here... had it since mid July. It's pretty good-I can get around 350KB/sec downloads at times (around 2.8Mbps), but I think uploads are capped at 15KB/sec (around 120kbps). Might be different depending on where you are. IP addresses are generally dynamic, but you're only assigned a new one every few weeks or so.
I live in a somewhat suburban area, but don't really know how many people are on Adelphia PowerLink in my town. Each town gets it's own set of nodes, though, I believe. I'm in a suburb of Buffalo, NY, which gets hit pretty hard at times with snowy weather, but I haven't had any problems with it as far as it being down during bad weather. Only problem I have with it is that the e-mail service is a bit unreliable. Or at least it was around the time I first got the service, don't know about now... haven't had anyone tell me about bouncing mail for a couple months.
Hope this helps give you an idea about the service!
JW