Was originally with NTL (ComTel) back when it was analogue cable, then when to Sky when NTL's digital offering was a bit pants and the Sky dish was the bees-knees. Then went back to Virgin Media and got 4 of those V+ boxes all over the house. Found the picture quality to be better (couldn't stand the way Sky would bear up in a rainstorm, even with an upgraded dish screwed to the house) - also, the broadband is proper fast, rather than just theoretically fast if you happen to live next door to the telephone exchange. Got a good deal on the four V+ boxes, plus all the movie channels, 20MB broadband and free calls to 01/02 numbers on the phone. My only grumble is the lack of live HD content (plenty on the VoD service, but only BBC HD on the channel line up). It's probably not enough to convince me to go back to the evil Murdoch organisation, but I may add FreeSat to the mix if the HD line up improves.
The V+ boxes themselves are pretty reasonable PVRs. They do all the things you'd expect, like series recording, pause, rewind, etc, and they give you access to a hell of a lot of on-demand content, much of which is free (especially on the XL package). You also get BBC iPlayer on Virgin, which is pretty good. The interface is (IMHO) slightly better than Sky+, since you don't lose the current channel when you jump into the tv guide, but not quite as intuitive as TiVo, which I still think has the best user interface out there (although the TiVo itself is pretty much a dead platform in the UK now)
Pete