I almost gave up on squeezebox as a transport until I changed one of the Server settings (Player - > Audio - > Volume Control - > Fixed at 100%).
The difference is like night and day and from there SB becomes a truly great performing digital transport with an open detailed sound.
It is actually an official recommendation that can be found in the squeezebox wiki along many others (http://wiki.slimdevices.com/index.php/HowtoBestAudioQuality).
Kazik