Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I use the same method but I write to Grouping, not Comments since it might have some information about the track.

When I need to backup/move, etc, I add the information to songs and when I need to rebuild the library I just create a smart list (with the grouping specification), select all the songs and change the rating.

Good way to recover all the ratings in less than 2min.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.