Very good doc. I'm not a big F1 fan and didn't really know this story before watching the film. I picked this based on other reviews I had seen.
It does make Prost look pretty bad, but I saw it a little different in that Prost was highly competitive, just like Senna. I thought the F1 officials were more to blame. Sport governing bodies, especially older ones, seem to lapse into politics.
The only real fault with the film is that I did find some of the voice-over and sub-titles a little hard to follow at times.