update: fixed the mode output so it's constant 1080i now. HD PQ is very good. I saw Apocalypse Now Redux last night, and it looked close to the HDDVD titles I've seen. I think if you have a 1080p display, you'll see even more improvement. (I think my set can only resolve about 1200x900 anyway. )
SD PQ is MUCH better. For ex, TNT SD on D* is really horrible, but on F* it's comparable to TNTTHD (for SD shows, obviously). Actually, it's arguably better since you have the choice to not stretch. In fact, the SD channels look close to OTA digital channels. Some channels are duplicates. The lower numbered ones I assume are analog. They look just as good to me as the digital (take that, Jessica Simpson).
I can't see any difference b/t local HD and OTA.
Now, for bad looking PQ, see the music channels
In short, you can't go wrong PQ wise.
As for the DVR vs the d* hdtivo, I miss the 30sec skip, the tivo sound feedback when you click a button, the smooth responsiveness of the uncluttered remote (the tivo UI team should get an award!!), 250gb vs 160gb HD. On the positive side, the guide scrolls so much faster, channel changing is faster, setting up a recording or season pass is nearly instantaneous, guide data go for like 2 weeks, and it doesn't take 5 mins to come back from a power loss.
now if they add food and hdtv hd and give me an option to add an ext. drive, I'll be one thoroughly happy camper. oh and lower the price too or give me some freebies for being an early adopter