The title says it all: Mary Elizabeth Winstead is excellent in this role. The movie itself, however, is not good. The characters are not developed. The flow is not organic. The structured reveals that lead to the movie's denouement are so forced that authentic emotional truth reduces to cliche. I am less forgiving of movies like this because they (attempt to) manipulate the audience. A better movie would illicit compassion and empathy through the identification with the character, perhaps. All About Nina, rather, vomits telegraphed "depth" (which is, in truth, shallow) all over the screen in an effort to bypass development, story, character arc, and narrative and get to the "point". The truth is that few people are going to climax if their lover doesn't pay attention. Here, the "lover" is the screenwriter/director who doesn't pay attention to any of the needs of the viewer, In an attempt to "move" the viewer, we're manipulated at every turn. The big moment of the movie, however, fell on its face. There was nothing true about it for the story; there was nothing true about it in the development; there was nothing true about it for the character. It was just meant to shock, and by implication explain the rest of the movie. Without the "foreplay" of good writing and characters, I wasn't turned on, and the big climax didn't give me the pleasure or satisfaction that I would have wanted after spending two hours in bed with this movie.
That said, Mary Elizabeth Winstead is terrific as the sexy, acerbic, wounded comedianne. There is more enjoyment in watching fragments of her routines than there is in the rest of the movie.
Is it worth a watch? It isn't. Do I recommend? I most certainly do not. Would I like to see more Mary Elizabeth Winstead? Without a doubt.