Worth watching?

I've been curious about this movie for a while, and am fascinated by unit 731 in general, but the 4+ hour running time, as well as the generally mixed reviews have led me to ask two questions: 1. Have you seen it? And if so, was it worth the time commitment, I do love a good long movie, provided it has quality material to fill the space. 2. Are there any other movies about 732 that you'd recommend watching instead, I've hear Men Behind the Sun is quite good for instance...