Ok, I just got done running a few more comparisons, so I hope this helps...
I compared the sound files from the Google Code page using Charity, LithMod, UD 0.8.0 and UD 1.0.0… noticed NO difference between the different ROMs. Those files didn't sound bad at all. I wouldn't say CD quality, and I could hear a little bit of digital distortion in the vocals, but that may be due to the files only being 48kbps.
I also went back and compared Pandora while I had the different ROMs restored on my phone, and there IS a difference there. Using LithMod, I couldn't find a single song that was decoded properly. Using Charity and the UD ROMs, I was still getting roughly 2 of 3 decoded properly. So the question is, why did the sample files play fine, while Pandora is having issues? And, why are the Pandora issues sporadic?
Also, I don't know if you saw my posts in the other threads regarding D1 vs. D2. Why is it that the D2 doesn't seem to be affected by this decoding issue when both phones are using Android 2.2?