I don't know if it's fair to have Back on Black in the "usually very poor" category. I know that their earlier releases are notoriously bad, but most of the more recent BoB reissues I own are somewhere between good and great. Seems like they sorta turned their act around starting in 2008 or so - although I'm sure not everything they put out is gold
On the other hand, I agree 100% with Rhino in the "usually very good" category, their Black Sabbath reissues in particular are amazing