Altman hyponotised me with this commentary. Although he wanders sometimes, and gripes a bit, he is very entertaining. Best part is when he talks about how he put 8 swear words in the film to get an R so 14 year old boys wouldn't see the film.

The commentary by scriptwriter Julian Fellowes, who apparently stems from an upper class family in Britain, is very very interesting. He gives loads of background information on how such a house was run and explains, how convincingly accurate the movie is in the details. He also comments about the dramaturgy (uh, right english word? dunno) and how the characters evolve.
The other commentary by Altman is ok, but I cannot remember it very well. So probably it was not outstanding.

This is very good commentary. The writer talks in detail about the construction of his script. Also he talks about missing scenes and information about the plot through the dialog. There has been a lot of research about the houses in 1930. We get more information about the living in these houses. This is a perfect addition to the movie. I prefer this commentary to Altman’s track.