I have had both services well before working for Virginmedia and had SKY removed within 4 months because after 3 boxes and long waits for engineers we were able to get out of the contract because they could not fulfil the terms and conditions of service, also be aware that after 12 months they will charge you for any engineer visit.
Here are some other thoughts for you to peruse.
http://www.cableforum.co.uk/board/11...l#post35105603