Last time I tried (which may be old): performance, opaqueness in what the musicbrainz magic is supposed/about to do to my files, lack of features and UX conveni

Last time I tried (which may be old): performance, opaqueness in what the musicbrainz magic is supposed/about to do to my files, lack of features and UX conveniences making it impossible to reproduce my stupidly picky tagging / filenaming scheme :)