The Tivo box is outstandingly good and well worth the usual Virgin gripes (currently: No sky atlantic, not all sports or movies in HD).
It should also be remembered that it is Mudoch Co restricting the channels virgin can show; Blatent monopolisation attempts - that go unpunished as no one can hold a candle to him in the industry (They tried with phone hacking, but he still got away scott free!).
You can't blame Virgin media for not having certain channels really. Aklthough; if they are must have channels for you then fair enough.. Go sky. IMHO The package they do have though is very good and competetively priced, etc also.
The counter argument for Virgin above all others though would be the indian call center experience. Now I've not had sky so don't know how good Sky's CS is: But yes; it is appaling with Virgin. Absolutely fine if nothing goes wrong, but getting them to understand the issue is nion impossible (Read: After 8 successive call center monkeys read their script and then say that someone will call you back when the solution isnt to turn it off/on again: Someone might eventually call you back. Who will then book an engineer and threaten you that if it's your fault it will cost infinity million dollars to fix. That engineer then won't bother to turn up; And they'll try and charge you anyway. Etc).