BBC HD is OK but I believe I noticed the difference, but then I encode material too, so know what to look for. BBC HD can afford to spend a bit of time on its compression too for the non-live material.
I don't think I have noticed the difference but I don't watch all that much on BBC HD. I'm mostly into documentaries and American imports these days. Last of the Summer Wine
will be a good benchmark though and the new series of that is presumably a few months away. Previously that has been hailed as an excellent example (picture-wise at least, granted a lot of people think the show itself is [censored]).
Now if Sky VoD were to offer higher than usual bit rates it would be a coup
Yes. If were given free reign I would implement it as a supplementary tuner and offer an option to restrict downloading to overnight. It wouldn't be VoD
but simply avoiding the dreaded 'clash' and not having to play 'shuffle the schedule' with +1 channels would be nice.