I'm using MusicBrainz Picard for tagging my music library and I'm not unhappy with it. Yet, sometimes it feels a bit clunky and I'm wondering if there are other good tools out there. What do people use? What are the major pros of these tools? Let's collect some recommendations here. I'm Linux based, but for the benefit of others don't restrict yourself!
I use beets in my setup and I am pleased with the results, keeps my library nice and clean. It is very capable by default and you can extend it even further with plugins. It will do fine importing well sorted albums and if you have a mess there's also tag by filename and acoustic fingerprinting. You can use multiple metadata providers and adjust their weights for preference. It's well documented and multiplatform (it can also be deployed as a container on a NAS system and manage of your imports). The biggest drawback is that you have to read a few pages of the docs before running it or do some dry runs.