McKay's use of a narrating character is sometimes helpful in providing context and continuity, though I think it worked better in The Big Short.
As a bio-pic, Vice does a good job of capturing Cheney's drive for power and his devotion to his family. Complicated people are generally difficult to depict in film, but McKay and the team he assembled gave it an effort worthy of some awards.
I found some of the editing a bit quirky to the point of distraction, but I definitely recommend seeing it. Be sure and stay to the end.