Other than Crowe's singing (which isn't terrible), the musical absurdities (which is just a wavelength thing), & its extreme sincerity (which I consider a strength), it's pretty unimpeachable. There are so many powerful moments: Do You Hear?, Empty Chairs at Empty Tables, the battle on the garbage barricade, etc...and, of course, I Dreamed a Dream. Say what you will about Hathaway being a bit much at times; she was put on this earth to perform that scene.
Review of Les Misérables
