Having a son-in-law that has Aspergers symptoms, I found the movie to be quite realistic in a non-Hollywood way. It didn't stoop to many of the clichés that several movies trying to tackle this subject fell into.
The lead actor did a great job portraying the attitude and personality of someone with Aspergers. His portrayal was quite well done, and accurate to real life situations He obviously did his homework when researching the character and the side effects of Aspergers syndrome.
Unfortunately, I found the lead female character (and the script components related to this character) to be less than believable. My personal opinion is that people with Aspergers syndrome tend to have a lack of empathy for other people (as portrayed in this movie), so it requires someone with extra empathy and forgiveness to be able to understand and relate to them (unless of course the partner has Aspergers themselves, which helps them understand and relate to the other person).
She didn't portray herself as an overly empathetic person, especially when dealing with her father's problems. Most children would be empathetic to their own parents first and foremost. She seemed to be forgiving of the lead characters flaws, but didn't really show a lot of emotion during the tense situations and unusual circumstances that cropped up.
Other than that, I thought it was a very good movie touching on this subject. If it weren't for the weak script and the issues with the lead female characterization, I would have given it a 10.
