Tags don’t work right: Another common problem has to do with tags, lyrics, and artwork. Users may change tags on a Mac and find that the changes don’t propagate to iTunes Match. When people change artwork on their computer, it’s not reflected on new downloads to their iPhone. Lyrics disappear, play counts and last-played dates don’t update, and more.
McElhearn lists a lot of annoyances with iTunes Match, but the tags not propagating to your other devices has to be the most annoying for me. I would love to see song Lyrics tag in-sync across my devices.