I'm not satisfied with tagging software on OS X either. I used The Godfather back on windows, and while there was a bit of a learning curve, I became very fast at tagging lots and lots of files.
To me FreeDB lookups are critical, and iTunes didn't have the search/replace features nor the ease of multiple updates I found elsewhere.
One promising solution is
Musorg but it's only at 0.2.2 and is a bit buggy and unfinished. I'm hoping that spreading the word will get more people interested in it and spur on the developer(s).
AFAIK, it's designed to be simple, light-weight and fast; Has FreeDB searching, and replace tokens for renaming.
Another more developed program is
TriTag at 0.8, and does about the same thing. It's UI isn't as streamlined, but it does the job.
HTH
Oh, and both are open source.