Pretty solid biopic (albeit with some stuff fudged.) Cranston does a nice job and the supporting players are good, especially John Goodman who is always good. Louis CK kind of played himself but he wasn't distracting. Helen Mirren is good but doesn't have enough to truly reach Marcia Gay Harden levels of The Woman You Despite (although, make no mistake, her character is despicable.
I didn't know the story so there were some surprises but I think the direction and cinematography kind of gave it a TV feel and wars of attrition just aren't as dramatic. I liked it better than Concussion but would probably place it in the same echelon of biopics. Good, not great.
Ultimately, I think the central conflict - being questioned - was handled so swiftly and I'm not sure I bought Trumbo's contention. Or, at least, I would have liked to see more discussion about it.