In the past week, I have seen The Machinist, The Fountain and Babel. Babel was barely an hour ago.
I honestly enjoyed 'The Fountain' the most. It's trippy, deeply romantic and screws with your mind in a cool way - and I imagine it can only get better with some drugs. The Machinist's ending was pretty disappointing but the movie had great atmosphere and it was hard not to appreciate the effort Bale put into his character.
For a two-and-a-half hour movie, it is mildly annoying that Babel doesn't even have an ending.
Oddly, it was the Japanese story-arc (the one everyone seems to like the most) that I didn't like at all. This is just my opinion but Morocco and Mexico was all this movie should have really been about. The overall theme of the movie is best captured as 'sometimes, bad things happen to good people thanks to normally-good people who sometimes do bad things because they had a long-overdue stupid-moment.'
While both 21 Grams and Babel are about death and tragedy, I liked the revenge/redemption theme of the former far more than the communication-breakdown study in Babel. 21 Grams was simply perfect, five-star material. This, I would give three at most.