We have recently moved from Virgin to Sky, mainly because of the lack of technical care they showed us. We basically lost all functionality on our boxes as they were not talking to the server. This lasted a couple of months, no series links, no TV guides and no catch up, all services they claimed were added value at no extra cost, which was untrue if they even bothered to look at the bills they were sending out.
I cancelled my contract with them and they wanted to charge us the £240 for breaking the contract, after numerous e-mails and letters using the resolver online service, and pointing out that we were only still in contract due to the fact they blew our homehub up when they launched superfast broadband, they cancelled that bill.