this the other day, and it's a very effective and well done history of DC Comics. the best thing about it was seeing all the writers and artists talk about various characters and things. I'd never seen Neal Adams talk before, and Marv Wolfman doesn't quite look like what I remember anymore.
of course, anyone who likes comic books will know most of this if not all of it. Marvel Comics does get mentioned, a little bit, as Julius Schwartz mostly jokingly takes credit for helping create the Fantastic Four. Julie was awesome.
so I recommend a viewing, just for fun. there are no real glaring errors that I saw, except they left out the Multiple Earths completely, which is kind of a interesting thing, since it was a great idea.