Which one would it be?

I'd like to know that too. So far I've only found buggy ones.

ID3 tags seem to be generally quite a mess. When editing those with different programs, you may end up with stack of duplicate tags in the file. I once started to wonder why some files didn't seem to take the edits in use, but it sticked to old ones no matter how I tried to remove the old tags and edit/add new ones. Then I checked the file in binary mode and saw that there were many different ID3 tag versions... both ID3v1 and ID3v2 (of course), but that wasn't enough, tags were saved 3 or 4 times there, and when I tried to remove/edit those it only changed the last ones, but the first one popped up with players always.

There's one unreleased MorphOS native editor from a well-known MorphOS developer, which could be quite good if finished :) I've been using test version of it occasionally. Works quite nicely if you know how to avoid couple things. But the problem with it is that you can't clear all the old tags with it if you have previously mentioned kind of files.

Then I found MP3TagEditor which can remove both ID3v1 and ID3v2 tags (you can repeat the removing until files are clear in multiple tags situation). It's 68k native and quite crash-prone, but if you're careful, and reboot after you've done, it can be used mostly successful. Check the log and learn to avoid the worst hits :) This is what I've been using now...

Couple others found from Aminet were quite horrible...

In old times I also used internal editor in AMPlifier (music player), but it only supports ID3v1 tags...

Anyway, if anyone knows or finds any better software for this, please tell!

Or port any of the open source ones if the native one can't be finished. But it would be really cool if it could be integrated with Jukebox

Jukebox should stay a player and nothing else. The sense of a player is to play songs, not to edit them all the time. For editing, MP3TagEditor and other tools are better off.

I'm usually against bloated software doing everything they shouldn't, but OTOH, it was pretty handy with AMPlifier, that when you noticed a song with incorrect tags, you just could correct it and save while listening the already loaded song. No need for extra work to start another program and dig out where the song you were listening is to load it, etc. In this case integrated editor would be quite handy.