Even at it's best, the sat channels have a picture that is notably softer (when I compared sat networks to OTA ones). I suspect this softening of the picture lowers its bitrate, and that is why E* is doing it.
They are definitely softer, but sitting 9' away from a 50" screen, you are hard pressed to tell the difference. When I am 7' or closer the difference is more apparent.
But they have made great strides since early last year. Even at 11' last April, the picture look terrible.
Well, after all this, and the BBC coming to HD, but on a sat we don't get, it's moot. Wife & son decided it's not worth getting new dish for that (or any of the 9).