I would imagine that this has been discussed here multiple times but my searches have turned up little. I have tried the godfather and mp3tag and musicbrainz tagger but none of them seem to be either easy or accurate.

Ideally I would like a piece of software the searches multiple databases and sites (freedb, gracenote, musicbrainz, amazon...), identifies possibly incorrect tags and suggests the best fixes. It should also identify slightly different variations of the same bands and allow me to correct them all as a group and in general just help me clean up the tags.

It must work with FLAC as well as MP3.

Any suggestions or links to previous threads (I know they must be out there, I just cant find them)

No one?

The closest thing I know of is musicBrainz. It's reasonably accurate, and fairly easy to use once you get the hang of the rather ugly interface.

I tried musicbrainz but it was very clunky and identified only a small percent of my collection

Did you try the musicbrainz Picard ? For me, it worked perfectly. It is more efficient on tagging albums than the 'regular' MusicBrainz tagger.
Some other applications use the MusicBrainz Database as well - but atm no names come to my mind.

Ill check out Picard. They link to a number of apps on their site that "use" musicbrainz, but when loading them up and trying them I couldnt find any evidence that they actually did nor could I get them to do what I wanted.