Comment on Tagr

The good: nice & clean UI, tagging is done with id3lib.
The bad: only support 5 tag fields (artist, album, genre, year and comment) and cover art, you cant customize most of the formats (like filenames format, or using id3v1 or v2).
Overall its well designed, but I guess mostly thought for developer's own use and not targeted to users in general, who may have a personal tagging scheme.