What criteria are used to denote one commentary as "better" than another? What are the hallmarks of a good commentary? I was watching "Crossing the Threshold" with Fr. Mitch Pacwa last night and he was saying that when starting a bible study it is good for each member of the bible study to get their own commentaries.  He mentioned a good one being St. John Chrystostom. But I've never seen a whole lot in the book store coming from other Catholic sources. 

This however, isn't a Catholic question specifically (although pointing me in the right direction is an instant +1). The main point is, what to look for in a bible commentary, especially when the New American Bible's footnotes just aren't quite cutting the mustard (not that they were intended to).
christianbook.com has a commentary page that lets you refine by "theological tradition", among other criteria. That is probably a good start, and will at least let you find commentaries written by Catholics.

Additionally, you could look a commentary up on bestcommentaries.com and read what reviewers have to say about it. That might not tell you whether the commentary is "safe" or not, but it should at least tell you what perspective the author has.