always nice to see something of such utility pop up. musicbrainz has most assuredly been around for what seems like forever now, and there's a reason for that. their tag database is second to none as far as im concerned. unfortunately for me, the only music I keep locally is my own music that I've made, and I can almost guarantee that that wouldn't be on there. plus i tag all my music properly to a point that might seem religious and obsessive because I hate music files without metadata (which is why I export in mp3 as well as wav; wav for higher quality, and mp3 for labeling purposes; I could probably just use flac but compressed audio like mp3 also has the benefit of being less space intensive).
either way, nice to see it