I have Sky TV. There was a lot of bad press when the Sky Broadband service was first introduced so I decided against moving my broadband to them and instead chose Be, another high speed LLU provider.
I have been relatively happy with Be but a few things have come to light which I wasn't aware of before I migrated. Those on the Lite package cannot request their latency to be switched over to fastpath, something that can increase speeds and ping times. Also the Lite package has a slower upload speed which also seems to have an effect on the download speeds, limiting them to ~70% of the connection speed rather than the ~85% of the connection speed I could be getting. My connection is fast enough...most of the time...for my uses, but I feel a little misled.
Sky do seem to have got their act together and I am seriouosly considering them for my next move, will save a few quid and have unlimited bandwidth, but I am in contract until March next year. Hope the service remains reliable until then!