I haven't seen Cloud Atlas, and hence cannot comment on the interplay between the music and the movie, so I will restrict my comments to the standalone quality of the score:
While the music from the action scenes is fairly typical of what you would hear in other contemporary movies, the real strength of the Cloud Atlas album is in the main theme - "The Atlas March". For those that watched the 5 minute trailer for the movie, "The Atlas March" is the opening music for the trailer (and first track of this album), which is rounded out by M83's "Outro".
I'm a fairly avid movie score collector and it's not often that you come across a theme so awe inspiring and refreshing - kudos to the trio of composers on a job well done!
Notable tracks (favorites*)
1) Prelude: The Atlas March* 3) Travel to Edinburgh 10) Kesselring 16) All boundaries are conventions* 18) Chasing Luisa Rey 20) Death is only a Door 21) Cloud Atlas Finale* 23) Cloud Atlas End Title*