Terrific acting and a naturally compelling story, adapted quite faithfully from Peter Morgan's play (which was nominated for multiple theater awards), translate well for the screen. If there are times it glosses over a bit or when director Ron Howard overuses the faux-naturalistic, floating camera technique to give it contrived immediacy --though he thankfully cuts back on that as the story takes off -- Frost/Nixon is a winner.
Howard and Morgan use mock interviews with the actors as character looking back soon after the events are all over is a forgivable contrivance as it does fill in some of the gaps quickly enough; this was a suitable solution to replacing the play's technique of having James Reston and Jack Brennan (from Frost's side and Nixon's side, respectively) narrate the story for perspective. Here Sam Rockwell's Reston and Kevin Bacon's Brennan, both excellent, fill that space just fine.
The film expands the visual scope; my mom, who had seen the play in NY with the same actors, told me afterwards that she found the film worked even better. Just as it was on stage, this is really Langella and Sheen's show and they are both remarkable. And here you get to see these actors capturing both men's anguish in close-up. While Langella doesn't physically resemble Nixon literally, he becomes the man, capturing the jowly sulkiness and sweaty shiftiness. The script and film do the seemingly impossible, as well: make Nixon almost sympathetic. As Langella gets under his skin so do we. Rockwell's Reston worries in the film at one point about how Frost's interview style could make people sympathize too much with a man who some considered a war criminal -- and the film's central struggle is about that very worry -- but Frost/Nixon does not make us approve of Nixon's actions. Only understand what lead him to act as he did, understand his own psychological demons. Just as MILK makes one understand, but still abhor, Dan White's ultimate tragic decision in that film, Frost/Nixon shows us a man, not a monster, who did monstrous things.
It's not a home run of a film, but it's both engaging and illuminating -- and the cast is outstanding. Besides, Langella and Sheen, Rockwell, Bacon, Oliver Platt, Matthew Macfadyen as producer John Birt, and Toby Jones, expertly moving from Truman Capote-ishness to Swifty Lazar-ishness, are all superb.