I really enjoy this movie! It makes no difference that it's B&W, that the quality of the film is "ancient," that many of the scenes seem artificial, etc. The story itself and Cooper's portrayal of York shine with quality and authenticity.
For me, there is one moment in the film that I love above everything else. To set the scene: A drunken York bent on murder is struck by lightning as he rides his mule in a storm. His rifle has been shattered but his mule is not injured.York hears singing in the nearby church. Not knowing why, he enters the church very slowly. As he moves down the aisle, the puzzlement in his eyes suddenly changes to recognition and understanding and he begins to sing along with the congregation.
That instant of his "conversion" is for me the best few seconds of a movie that is timeless. When you watch it, remember those seconds, The acting is superb.