Here are my comments on the Phoenix area digital stations picture and sound quality. Keep in mind that with my extensive tweaks and rotor controlled OTA digital/analog antenna, I get fantastic reception, and my analog OTA local stations come through clean with no audio or video noise at all (took lot of work/tweaks to get to this point, believe me). Unless I note that the digital channel actually has HD programming, it doesn't.
Note that my analog OTA channels, and DirecTV non-HD channels, are at 720p using my Dwin HD-700 CRT projector and Transcanner 2 scaler.
digital 17-1 (analog Ch 5 CBS) - Dolby Digital 2.0 sound at half normal compression rate. Regular OTA Channel 5 is best sound and picture and even DirecTV local channel 5 is next best sound and picture quality.
digital 45-1 or 26-1 (UPN analog Ch 45) - Same as for digital 17-1 above.
digital 31-1 (FOX analog 10) - Same as for digital 17-1 above. Except the Dolby Digital 2.0 sound is regular not half-rate compression but still the analog OTA audio is the best and next the DirecTV local channel audio.
digital 36-1 (NBC analog 12) - I even like Ch 12's non-HD programming, and their HD stuff - Crossing Jordan, Jay Leno, and now The Winter Olympics - is wonderful. Dolby Digital 2.0 at the normal compression rate sounds nice, altho HD-Net has same Olympics in Dolby Digital 5.1 and I can hear that the latter is better.
digital 56-1 (ABC analog 15) - About same as Ch. 12, and ABC does have some HD programming.
Note that for most folks, the digital channels, even if not HD, will be better, because most folks don't have good enough reception and/or noise problems with the analog picture and sound. But I don't have such problems anymore!