Sometimes I think DVD audio commentaries are a lose-lose situation for the filmmakers involved in recording them. First of all you're forced to cram the entire days, months, and years of making this thing into a real-time babbling brook of interesting anecdotes, pertinant technical knowledge and just generally interesting stuff, however, I think no matter how successful one is in this endeavor you'll always find someone who will lodge some strong complaint against your approach. If you get technical they'll whine "he's talking about all this crap I don't care about." You might be "too nice to everybody" but then you can also "put everyone down too much." If you discuss the technical shortcoming of your piece they might complain that you're "putting EVERYTHING down," with a sense of shock and dismay. Personally I've often searched for a qualitative sense of what makes a commentary either "bad" or "good" but I've never really been able to nail it down because honestly I don't think such criterion exists. Often when people speak of their favorites commentaries they're talking less about the tracks themselves and more about the people on the tracks, the level of respect which they give them and the individual tenor of their voices.
Ultimately I think a "good" commentary track is one where the commentator attempts to imbue a sense of honesty and humanity in a nice little informal monologue over the material which is being presented before him or her. I really shy away from group or "party" commentary, because in spite of the appearance of a loose and down-to-earth atmosphere these tracks are probably some of the most pretentious of them all because all of the participants are all worried about the whole "group think" of the thing, they begin to speak about things which the group themselves finds important (with little regard for either the viewer or viewing material) and before you know it the alcoholic beverages come out and the listener is left with the limp, diluted efforts of a group of inebriated people mentally wacking themselves off, a true waste of time for anyone save for those who just want their lonely room to be filled up with voices, if they're stupid and moronic-sounding ones. I guess I'm a little harsh here, because in fact I think there are a few group commentaries which are surprisingly interesting, focused and funny (the commentary on the Unhinged DVD really surprised me) there are dozens of examples where interesting anecdotes and info is lost in the signal-to-noise ratio. So I like solo commentary. Also, with FBN it took me a week to record the whole thing - I did the first half in one sitting then I spent a week trying to think up ideas and information and add them all in. I tried to make the track a mix of conceptual ideas and production information but I'm sure there's lots of bits that I missed but ultimately with commentaries you just have to "let it go" and realize that these tracks are the holy founts of eternal knowledge which some make them out to be. At their best they can be very inspiring, however.
I think the bottom line with commentary, something which I think many commentary critiquers on all sides refuse to accept, is that there might simply be "commentary people" and "non-commentary people." I think the non-coms outnumber the pro-coms. How many times have you finished a movie with your friends and said "hey, let's flip on the commentary!" only to be met with the weirdest facial expressions in your life? I've found many people barely listen to commentary, while on the other hand you'll have people who will rabidly devour them. The deal is, I don't think it has to do with one's own exposure to DVD or any personal cinematic sophistication. I think it has to do with how people process information and are receptive to learning. Do they like being lectured to, read to? Many times I think a non-commentary person will tolerate a very well-done and entertaining commentary but it's simply not in their nature. Perhaps this is a stretch, but perhaps not?