I heard the HD radio that radio shack featured over Thanksgiving. It was a good and it sounded good. I have the Boston Acoustics.
HD does not go as far as the analog signal,IMO. However, like a digital conversion from analog would be expected to be, the sound is significantly better. But, when it's problematic, it disappears. No static- like analog vs digital cellular, if you remember back that far, you either have it or you don't.
NEPA will be a tough HD conversion, since simulcasts will require a double investment. Unlike processing which can be split to cover simulcasts or translators, HD is a function of the XTMR so it will be expensive.
I believe Entercom is in the HD alliance, so I'd expect them to go first, at least on 98.5 and 101.3.But even there, would they add it on 107.9 and 95.9? $$$ for 4 antennas, xtmrs and HD processing. But if they didn't include the simulcasts , how would they promote or retrain their listeners???