As for Scott's comments and peoples take on his initial HD quality feedback, there is certainly a difference in the local MPEG4 channels and the national HD MPEG2 ones. I think D* to fight for space, has compressed the hell out of them. What most of us are finding is that the newer MPEG4 ones are pretty darn good and as close to MPEG2 OTA as you can get. Most don't and cant notice any difference. I am sure there is always going to be something since you are modifying the original feed but its good.
That being said, when the new sats launch and the new HD comes out as MPEG4, the channels WILL look better then the current compressed MPEG2. What will be interesting to see is how quickly they convert the current MPEG2 ones to MPEG4 forcing you to use the HR20 or H20 receivers to see them. They might mirror them for a bit but I sure hope they move quickly to MPEG4 as it is clearly better then the current MPEG2 HD.