I just came across Musicbee and was absolutely stunned, I immediately thought that it was what Songbirg tried to be but failed at being.
So why it is good, just check the features.
Unbuggy library management? Check
Even with 10000+ files? Check again
WASAPI/ASIO support? Check
Auto tag, Album art search? Check
Transcoding (including lossess)? Check
Smart playlists? Check
Auto lyrics? Check
Last.fm artist biography, genre... ? Check
DAP management? Check
Cue files/AccrurateRip Check
All of the above out of the box? CHECK
And best of all it's has a reasonable memory footprint and runs without lag when searching for something.
As for the cons, fb2k is remains faster and more responsive and it only runs with windows. Still a super app though.
EDIT: More cons, not open source, but it's a philosophical issue rather than one of functionality.
Edited by khaos974 - 8/30/10 at 10:16pm