Which DVD's in all series have the best commentaries

[A Cousin]

I am probably going to be the lone voice in the wind, but I prefer the commentaries with the Producers, Directors, Writers and Script Editors because I find they give more insight into overall plot development, character development, writing arcs, cinematography and filming techniques. I have only heard them once through so I'd need more viewing to get much more specific but I particularly like the producer Andrew Woodhead and the script editor for S3 (whose name is shamefully escaping me at the moment ) because their commentary comes from the POV of someone who is concentrated on the series as a whole and not one episode or one character.

The best actor commentary for me comes from David Oyelowo hands down. Maybe because he is a director as well.