Compared to the past Confidential episodes, this impressed me the least.
There was a final clip montage done as a tribute to the ninth doctor's reign, some information on the development of the supreme Dalek, a nice explaination of the regeneration sequence and for Jack's farewell kiss (the documentary makes it sound like he's gone for good), but the rest of it just feels like a recap of what was just shown in the main episode.
What I really wanted to hear about was a nice little tidbit about David Tennant's doctor to hold us over until December, but no such luck.
This one episode aside, the Confidential series really helps to show just how far the show has come since the early days in a way other documentaries couldn't.