This movie reminded me of The Room -- except The Room actually had a plausible excuse for being so bad: it was deliberate. While watching Atlas Shrugged, I don't think I went longer than a two minute stretch without either cringing or laughing out loud at the poor acting or script.
As someone who hasn't read the book, I guess I necessarily will have a different experience of it than those who have. So, for those who have read it and liked the movie, and want to know how those who haven't will receive it, this is how: the budget of the movie was apparent in every scene. The budget was practically the main star of the movie. It seems to me as though the plot was moving way way way too fast. There was constantly, constantly, something going on, some new turn in the story. I personally think a movie needs some down time, some break in the action. It's exhausting to watch a movie that's so full of words, and that's what this movie was: full of words. Nothing was left to implication or guessing, seems like everything that could be said was said. No subtlety.
I personally don't think this movie will attract much new interest in the book or in libertarianism. It may inspire some people who already wanted to read the book to read it. It also may influence some people who might have wanted to read it (like me) to decide that they actually really don't want to anymore.