Firstly, let me say, I bawled my eyes out during a good 50% of the film, and I don't mean sniffed away a tear, I mean full on waterworks. I will admit this may be to do with the fact I do the same in the stage show, but since the film had the same effect on me, it was a notable start. ;) However, there are differences to it as well, one being something I had to get used to: the film is not as emphatically sung as the stage show, which, again, some folks may think would be obvious, since on stage, the actors are projecting to thousands of people, whereas on film, there emoting to camera.
However, I found this applied to the chorus numbers as well as the intimate solos and duets where the camera was right on the singer most of the time.This meant I didn't get as rousing a feeling around the chorus numbers, but actually, the solo/duet numbers gained something from the intimacy of the camera: I felt the actors had more of a chance to nuance their performances. The best example of this for me was Javert's suicide scene. It's a fabulous, dramatic mess of conflicting emotions on stage, but it has a hard edge on stage (at least in the versions I've seen). In the film, Russell Crowe pulled it back and there were levels of anger and confusion and despair. It also enabled a pause between the song and the suicide, a time for the camera to focus on Javert's conflict, which would not have worked on stage.
I wasn't always happy with the full on close ups for most solos and duets, it began to feel claustrophobic, but it did work sometimes.
Going back to the chorus numbers - maybe my surround sound system was not good enough, but there's a lot of emotion a crowd of people on a stage only yards away from you can convey and I didn't get the same effect from the movie. In fact, for me, these songs came off muted. The only one where it really, really worked, was the funeral of LeMarc, where the song starts small, the camera focusing in on individual faces, and grows through both the music and the action, widening out to a full ensemble scene. This is where the new medium added to the story, because you could not have done this kind of movement of cast on stage. There weren't many places where this scale helped the story, though, since the barricades creation I thought was more impressive on stage, due to the stylising of the barricade. That bit felt as closed in as the stage show, so didn't gain anything.
I thought the performances of the main cast were excellent; Javert was hard and blind to the nuances of life until the very end of his life, when he is so confused; Jean Valjean is beautifully muted about the world until he rescues Cosette; Marius is, well, Marius, school boy on an adventure who falls in love; Cosette was much better than any Cosette I've seen before, maybe because her love for both Marius and Valjean can be shown better close up; Fantine captured hearts as she descended to desperation. One of the best performances, I think, was given by little Gavroche - feisty, defiant and braver than any man, and yes, when he gets shot was one of the moments I bawled my eyes out. Eponine, too, the tragic lover, never to be recognised until it's too late, kept me enthralled during 'a little drop of rain'.
I don't think I can pick out one single performance that beat all the others, though, because this was truly an ensemble cast. No-one was trying to upstage anyone else. They told the story together. So, all in all, I liked the movie. it had depth and gave me a different way of enjoying Les Mis. It may be unfair to compare it to a live performance, because they are very different mediums, but I'm going to anyway - this film was good, I'd recommend people to see it, but the stage is where this musical was born and where it has the most impact.
P.S. Oh, oh, I nearly forgot, Helena Bohnam Carter and Sacha Baron Cohen as the dishonourable Thenardiers are just exquisitely nasty. Nothing subtle about those two :)
And P.P.S - Note for my slash-writing friends, who might not have seen the movie - Javert/Valjean, the tension between those two is well filmed and performed and there are so many (little and big) shifts in the power dynamics, especially at the end where Valjean turns away from Javert and Javert lets him go, gun in hand, that there's enough material to keep an army of slashers going for years. ;P