I use to have Time Warner Cable through a Scientific Atlantic HD8300 DVR using the optical TOSLINK with a glass cable connected to an Apogee BigBen digital clock, which would feed my Zanden DAC.
I also had a SqueezeBox connected to the BigBen clock through a coax cable. Music was ripped using WMA lossless on my PC music server at the time.
All sources that connect through the BigBen become reclocked signals then feeding my DAC. This would essentially level the playing field for when listening to different digital sources.
Both MusicChoice channls on Time Warner Cable and SqeezeBox delivered digital from my music server were very very close. I suspect the optical TOSLINK connection was the weak point in the chain detracting from the cable box's performance. I'm not claiming I could even hear the difference, it was probably more 'in my head' knowing about the interface differences.
Both sources were 44.1k non compressed.
Internet radio is horrible, compression rates are the culprit. I try to listen to 192K stations only, and they are the only ones worth listening to IMHO.