The sound was fine in CCC Remixed (PSP), except for a few misassigned level tunes I heard about, which is why it's a little surprising that they weren't able to get it right for SGC.
Plus, the music is streamed, so it doesn't speed up where it's supposed to in the Sonic games, and in a few games it doesn't start or stop in the right place. The sound effects in most of the games sound off - either stretched-out and mangled or just plain wrong.