I'll admit that the idea of Spector's innocence in the death of the girl at his house had never seriously crossed my mind. A brave stand to take on David Mamet's side, therefore!
Very cleverly - but then, Mamet usually knows his stuff..! - he also focuses on the relationship between Spector and his defense lawyer, rather than on the dead girl or the actual trial.
However brilliant a producer Spector was, he has never given the impression of being anything but a full-fledged shithead, so it is hard to side with him, which actually is in the best interest of the film!
Excellent actors, obviously.
Sadly, I found it a bit boring...
As for Spector, I am still pretty much convinced he did it. Celebs have a way of getting off the hook in the US, no matter how bad they look, so for Spector to have been actually convicted, I'd say the evidence must have been rather overwhelming.