I have been on BT Anytime for 1 month now after transfering from Freeserve unlimited before it is closed down. So far I have found it to be very good.
I think there is definitely a link between quality of sevice and where you live. I live just down the road from "Tartan Gannet" at Maidenhead, it would seem that the Thames Valley area is generally pretty good internet traffic.
Regards
FBW