I have also noticed National HD PQ is IMPROVED about a month or so ago when someone first brought it up then. Aside from compression, the bit-rate is another very important factor in the HD PQ.
I must say, that our Sony in the living room really does wonders with cleaning up and processing to present a really great HD PQ given just about any format to deal with. I have very recently installed the DVDOEdge and it has improved HD PQ a bit, but to a noticeable degree. Things even look better on our older entry level Sharp, watching Dish HD.
Now, the really sad part is that, at least here in L.A., OTA PQ has actually degraded on several OTA locals, but it still looks good, but that means that this low PQ is what Dish is given to work with in regards to HD LIL. I have seen macroblocing and other artifacts on the OTA via direct or through TiVo and when a brodcaster is stuck working with MPEG2 only 19Mbs left over, we are gonna see problems.
Now, there is a noticeable, but slight, degradation of the KTLA Channel 5 PQ (via direct OTA connnection and TiVo using OTA antenna) is apparent, at lest to me. The KTLA PQ, even through Dish sat HD LIL, looked stunning, especially during the Moring News; it always stood out compared to all the other locals, even as KTLA operated 5.2 for This TV. Then I noticed that the luster was gone. The KTLA HD PQ now seemed less vivid, somewhat flat with less detail and a slight soft look. Well, I discover a few days later that KTLA has opened 5.3 for all to see and they will now be operating TWO sub-channels. Well, now I see. Just like the degradation of KABC (now sending out TWO channels in HD) and KNBC, among others, it is due to the ever increasing multiplexing and sharing of bandwidth. KCBS continues to look better.
The point is that the old gold standard of local OTA via direct connection is dying and that very few broadcasters actually broadcast the main HD in the full 19Mbs. In other words, now the local OTA is now an "HD lite" service, as well and, for the most part, should not be used as a reference to evaluate Dish HD PQ. It is all becoming degraded these days and will probably get worse, but still look "good" but not the really noticeably "GREAT" that full 19Mbs can provide. Very sad.