M was a great movie. I'm real big on murder mysteries in general, and M took a different spin on anything that I had ever seen, with the gangsters and police trying to find this murderer simultaneously. It does drag in some places, but not enough to bring the whole movie down. Peter Lorre's performance was amazing. If nothing else, you should watch the movie just to see him in the end scenes, at the trial. Great movie, I'd watch it again.