Beets music tagger help

[squirrellydw]

So does anyone use Beets music tagger and can help me a little. All my music is in iTunes and I have it tagged pretty well. I know I'm missing some info like genre and things but for the most part I would say 90% of my music is correct. Now the tags may not be 100% correct for each field for each song and that's what I would like to try and fix.

I'm a little confused with some of the settings, should I copy my music to a new directory or leave it? I'm think I should copy/move it, what setting is that? Also any idea how long it takes to go though about 150gigs of music?