Hi Lollypop - We actually did the same transition from virgin to sky so I can tell you what it was like. With Virgin we had good tv and the user interface was o.k. It was a bit slow but we could find stuff when we wanted it.
We switched to sky and the picture was sharper, which was good, and the tv choices were the same. The user interface was not quite as easy to use, which was kind of disappointing as we couldn't find shows we wanted to watch, and would gladly have moved back to virgin for the user interface. In that respect it was a significant downgrade from virgin.
The other thing that was weird with sky was that they had all sorts of ruses to fleece us for our cash. For example they offered us a free £50 M&S voucher to sign up to sky, but even though I phoned up three times and each time they said they would post it, the voucher never came (ever).
Also once we signed up we could log in to the website and check a box to add extra channels to our package (sports or whatever) but to remove channels from our package we had to actually phone up and stay on hold for eons, and then go through millions of questions and things. So deleting a package to save money was a major chore. We also tended to be on hold much longer with sky than with virgin, which again costs money.
So in summary, although virgin was a bit annoying and slow, virgin did seem quite virtuous compared to sky. Sky, by comparison very clearly using weird ruses to fleece us for money.
I've since read an article in the newspaper that says that sky actually have an internal policy of putting people on hold for longer if they pay a lot for their packages as they know that people who have a lot of money are unlikely to have much time to stay on hold. By putting these people on hold for long periods they can prevent them from cancelling.
In the end we cancelled sky and now just have freesat, but in your position, if you use your pay tv a lot, I'd be inclined to stick with virgin and just buy ds a laptop. Just my two cents worth of course and please feel free to ignore me if you just fancy a change. 