Well you can check out the prices yourself, cos it depends on what Channels you want.
I have Virgin, but I find it really unreliable. The disadvantages of Virign are:
1) It doesnt have Channel Sky One, ie no Prison Break ...
2) Sometimes it doesn't work
1) Catch up TV on demand service:
basically this a free service that lets u watch a few selected BBC and Channel 4 programmes in the last 7 days. Its useful cos you can catch up on EastEnders.. any time, and its free. But you cant record things - you can only choose what Virgin media records/is available
I've heard you have to buy a sky box, so if it stops working then its YOUR responsibility - ie you need to pay to repair. Virgin media repairs it for FREE, cos u dont have to buy the box - they "lend" it to you.
Hope that helped