I have ripped my CDs to FLAC (using dBpowerAmp), and does thus have almost 14000 tagged FLAC-tracks on my hard drive (~400 GB).
I thought it might be nice to add tags and connect them to the corresponding release and artist in Musicbrainz, so I downloaded Picard, selected all tracks, and asked it to look them up for me.
Results were unfurtunately underwhelming so far. After around 9 hours of work, despite the tracks being organized in a directory per album, and tagged with correct artist and title, over 3500 tracks are not matched, and it tries to change other tracks from being connected to the correct album to being "non-album tracks", even though I can find track on my album in your online database.
So far I'm thus quite disappointed with the results, but perhaps you know of some trick that I should try?
If you want me to send logfiles for you to improve Picard I would be happy to do so, but right now using it is not an option for me.