I've been using Pipex ADSL for the last month or so, and have nothing but good things to say. Having spoken to other users before taking the leap, I've yet to hear a negative comment.
The 10 day wait for activation turned out to be 6 days, *including a bank holiday weekend*.
This is not at all unusual.
The service never fails to connect first time, it has not dropped the connection once, despite sometimes being left for days at a time.
The 576kbps connection speed is the maximum, and Pipex point out that at times of high usage, your actual download speeds may drop as you effectively share a chunk of bandwidth with up to 50 other users. However, I have not noticed it dropping once, and downloads are scarily fast compared to dial-up. The progress bar fairly shoots across the screen.
Check out
http://www.adslguide.org.uk/
pilot-lite