Finally, I've found one that has the features/interface that is useful to me.
I don't really need lookups, I prefer to research the music myself for the non-critical tags. And I don't want to sort out all the compilation album data. I want to tag the file with the info from the first album it appeared on.
But that's what what's wrong with some other taggers. (Actually, Kid3 has some lookup features, but I think they are best used if you can put all the mp3 from a certain album in their own directory. I need to quick edit the Song and Artist tags for a bunch that are in the same directory as other files that don't need editing.
Kid3 allows you to scroll down a list of all mp3s in a directory, and when you spot one that's missing some desired tag info, you can stop and extract it from the filename, or from the other tag set. It displays both ID3v1.1 and ID3v2.3.0 (or ID3v2.4.0 if you config it to do so) tags for each file, allowing you to push the data from one tag to the other. This *should* avoid the problems of some tags not showing up in some players.
You can also select a group of files and set all their Artist tags to the same spelling, for example.
The editor is free and lots of other features, but these are the ones that I need. The only way it could be significantly better, is if it would just present files that are missing v2 tags, v3 tags, both, and those whose tags don't match the filenameing template. That would save *so* much time.