"Babel" is a heavy, long movie, but it is quite well done, engaging, and worth sitting through at least once. Everyone in the movie does an excellent job, though Brad Pitt and Cate Blanchett's parts pretty much could have been played by anyone, and maybe they would have appealed better, shone more, or had the quality that was just missing against everyone else, and the very powerful, well written storyline. Sometimes movies with interlocking stories just fall flat, aren't written well, but that is definitely not the case here.
That all being said, I think one watch in a lifetime is enough for this movie. It's so long, I don't know if I could have the patience to sit through it a second time.