I saw the documentary last night at the NFT. Quite good overall - very interesting sound recordings of Carol Reed and Graham Greene, and some interviews with Guy Hamilton and Angela Allen, and made a few good points about filming in Vienna that haven't been in any books. But it used far too much footage from the film, considering everyone watching will have seen the film already.
As regards OW, it was extremely critical. Some of this was justified - they showed a video of Welles claiming he wrote all his own lines, clearly untrue. But a lot of it seemed rather harsh - they said he ran off to Paris and Rome (which is true), but gave the motive as him wanting to earn his pay for as little work as possible. It made it sound like he was only interested in money - nowhere did they point out that the money wasnt' for himself, but for funding his films. They also reported that he refused to work in the Vienna sewers, saying something along the lines of "I'm an American, and everything in america is clean, why should I have to work under such conditions?" This, to me, seems distinctly un-Wellesian.
At another point, Angela Allen referred to OW as 'his little Lordship'. And a cutter or runner at Shepperton Studios made a very damning speech about him, effectively suggesting he was stuck-up, and had to be treated delicately, saying that ever since making his first film, he had become Citizen Kane.
The only good thing they put in regarding Orson was an excerpt from an interview where he said what a great director Reed was, and how good he was at working with actors.