I've never used itunes. Do you have the ability within itunes to group tracks by rating? If so, you could bring over each rating batch seperately, rate it on import in to MC and be done with it.
Thanks jgreen. That's exactly the way to do it.
Here is how I just did it:
1) I made a few new smart playlist in iTunes, one for each rating.
2) I exported the iTunes smart playlists in text only format (right-click the list name > Export Song List... > Save as type: Text files)
3) I opened the lists with Excel and removed all other columns except the column labeled "Location" that contains the filename paths. I also removed the header row.
4) I saved the files in text only format and changed the txt extensions to m3u.
5) I imported the m3u files to an empty MC library. The new playlists appeared in the Imported Playlists tree branch.
6) I rated the files inside MC, one playlist at a time.