I have used ACDSee (9.0) with success for metadata editing and I have found several apps simply "googled" for at CNET.com to further find those utilities that specifically edit metadata.
I have not yet found an editor that can edit ALL fields given one in Vista's "sort by" function in Vista folders.
I am also looking for a MD editor that can remove all MD information. None I've found so far remove all of it. It seems as if some files can "protect" their metadata?? Can anyone confirm?