He listened to hundreds of Steve's talks, studied art & topics that influenced Jobs, read Jobs' favorite books, obsessed over him for months, ate Jobs' diet, even learned to walk like Jobs (who has an odd gait, likely due to years of walking barefoot).
I got to see a screening of the movie yesterday with subsequent QA by Kutcher. Even though he's humble and doesn't claim to be an expert, it was borderline freaky how well Kutcher seems to understand Jobs. At least, from the point-of-view of someone who wasn't friends or family.
I consider him an expert.
Related: I like when RapGenius branches out from rap. I wonder if it will always be called RapGenius for non-rap content, or if they'll come up with a more general brand name. I think it'd be neat if RapGenius became as broad as Wikipedia.