We have been with NTL and then Virgin after the takeover for 9 years now and never had a problem with them.
There response if you do have a problem is very good too,we had the house fronts done up by the council under the regeneration scheme the firm that was doing it cut through my broadband and tv cable i got in touch with virgin and they where there within a few hours and did a good job.
also if you do go with virgin get a friend who has virgin to recommend you to them after its been installed your friend will get £30 off his bill
I have done this 3 times upto now.