I was lucky enough to see this in a cinema with a restored print. I had previously caught a snatch of it while channel surfing cable TV, and saw enough in about 30 seconds to realise that this was worth watching through if I got the chance.
I could barely speak at the end of the film. Pauline Kael called it one of the scariest movies ever made, and she was absolutely right. Robert Mitchum becomes the embodiment of evil, and his pursuit of the children is so relentless, and so menacing, that it becomes impossible to believe that they can escape. The images are brilliant; there's a depth to black and white that colour somehow lacks, and it is used superbly here to create a sense of brooding terror.
I didn't mind the homily at the end. Like everything else in the film, it is done with utter conviction, and this makes it work. Charles Laughton saw it as the indispensable conclusion to the film, and the strength of his belief makes it indispensable.
The images are so much part of the film that it must lose a great deal on the small screen, although my minimal exposure to it in that environment showed that it was still well worth watching, but if you get a chance to see it in a cinema, jump at it.