Leto is a great actor. But...
I honestly felt that this movie could have done without his character.
Every time the movie focused on one of his sub plots or mini-dramas, I felt disconnected from the movie somehow. I felt like I was watching another movie.
Then when the movie got back to the main plot I felt like it took me a while to connect again.
In contrast to Cages character, Leto's just didn't seem to belong in the movie. Or least not as much of it. It almost became a side movie, which I wasn't interested in after a certain point.
Now I know it's always good to mix in a bit of personal chaos, but I just don't feel like it worked in this movie.
I really can't put my finger on it... But if I were to compare it to another movie, I would liken it to Goodfella's and Liotta's character. Had Goodfellas not been as good as it was, Liotta's depiction of Hill probably would have been enough to ruin the movie. IMO anyway.
+++ Jason http://www.youtube.com/user/HaligonianType1