I am disappointed by the lack of a commentary track, though I was not expecting one since Nolan has not done one since Insomnia. Which is too bad because Insomnia's commentary track is pretty awesome, it actually recuts the scenes in the order that they were filmed and Nolan gets really technical about the whole process.
I will say that extraction mode doesn't make up for the lack of commentary but I find the featurettes fairly insightful none the less. Disc 2 is pretty sparse though, kind of surprises me they could not fit that content on Disc 1.