I know there is a lot of fuss about NTL but the reason I choose cable is because you get companies that provide ADSL blocking your telephone line making your choice limited.
I normally contact the board of directors if I am having problems and this has worked most of the time and if I did not get the response I was looking for, I at least got a reply.
My advice is that choosing an ISP depends on individual needs. I download almost 5 Gigs a days and that is why I need something that is fast and reliable. I have had issues with NTL but to be honest, their connection is quite good but customer service poor.
Check this link out http://www.uswitch.com/Broadband/ExistingUsage/BB_Output.aspx?ref=upmystreet%7ebroadband&SessionID=2XWX6%2bMoxYOZnO0OHB%2bVp2iBSv5TERjE
Or go to www.uswitch.com