It is certainly true that this is not the most accurate of historical documents, but then any historian would tell you that all history is in the interpretation and so the movie is as useful as your interpretation. The performances are excellent, Branagh, in particular, is outstanding, he is every bit the portrayal of the chillingly pleasant monster. The message is powerful, the acting and direction cold, calm and calculated - within 1 hour the holocaust was decided upon; the moment where the topic of discussion is how many and how fast can they be culled? is particularly sickening.
From an historical perspective i found the following very interesting: Hitler based his party structure on a chaos theory in that he had simple overlapping functions, so that his subordinates would always be engaged in in-fighting, instead of challenging him. It worked remarkably well. Here, in motion, the director shows the in-fighting, but on this part of domestic policy (internal to the Reich, at any rate) the decision was swift and unanimous, Heydrich alone held the power. Utterly intriguing.
What may make this more interesting for anyone, might be to read Hannah Arendt's account of Eichmann's trial in Jerusalem, which is published by Penguin.