The best part of the movie for me was the music by Jóhann Jóhannsson and the cinematography by Roger Deakins. I read Roger was inspired by some of the photographs of Mexican land in a magazine. Some of his wide rotating shots from the top angle were just beautiful to watch. And combine this with the haunting and engaging music just upped the ante for the dramatic and thrilling moments in the film. Roger's previous credits include classic movies such as The Shawshank Redemption and it is only now that I am learning of his name but I will never forget it.
Benicio Del Toro's character is not developed enough but is still a very interesting and mysterious one and at times towards the end had traits of Michael Corleone which isn't a bad thing at all. The movie starts off on the fourth gear and never goes down on the pace which is a joy ride.
A must watch in my opinion. But of course you would have already done it by now. :)