Ok, i'm a bit confused, so it'll be great if some one with more tagging experience will clarify this for me.
It's not mp3tag problem thou, anyway..
I have method of how i tag various artist releases:
If it's a mix cd, i put a person who have done the mix in BAND tag, and original artists i put in the artist tag for every track.
If it's a compilation, i put various and publisher/person in BAND tag, and original artists in artist tag for every track, for eg. Various Sub Rosa  An Anthology Of Noise & Electronic Music.
recently i tagged mix album using freedb, and ended up with 'various' in ARTIST tag for every track, that way i lost all original artists tag info.
The only way to prevent that is to use tag trackartist, but i don't know if i want to introduce another artist tag in all that, it just complicates thing even more.
What is the right way to deal with those problems, or at least what is your preferred method?