So long story short: iTunes is a POS and messed up the tags for thousands of my MP3 when I originally encoded. A specific version had a broken MP3 tag editor it appears and this was not found by me till I started using other tools/devices to play these MP3s.
Currently in my MC Library under Audio --> Artists --> Unassigned I can see all the files that have improper tags. I want to get these updated properly so that MC can use the tags properly, but more importantly other devices can display the information correctly (Android phone and my Chev truck primarily).
So far I have tried the following:
1) update tags in MC using Library Tools --> Look up track info from online database. This has been mostly unsuccessful as if I'm lucky 2-3 tracks per album come back with valid info, and even then the data is inconsistent, e.g. Genre is different for the songs that come back. There was also a "bug" in my portable install that didn't update the file tags themselves, which has been fixed in newer version, but basically caused me to redo a bunch of tag updates.
2) re-rip the CD. This has been almost 100% successful but is time consuming and I likely have a couple of hundred discs to do.
3) use an external MP3 tag editor which is maybe 80% successful as it uses more mainstream data sources (discogs, amazon, etc)
If anyone has any other suggestions to make this less painful that would be great.