I wasn't a HJ fan or RC fan when I went to see the film for the first time. I was very skeptical,and not very happy about the casting,but having seen it four times now I'm a complete convert,and think it really worked.
I love Philip Quast and Colm Wilkinson,yes I know he was in the film,but if singers of their calibre were cast in the main roles,they'd really have to tone things down because film is a much more intimate medium than stage.
When I heard some of the songs before seeing the film I wasn't at all impressed,HJ's excessive vibrato particuarly annoyed me,but four viewings in and my opinion has really changed. I loved him in the role,loved the emotion and conviction he brought to the role,and now I'm able to actively enjoy his singing.It wouldn't work on stage imho,though I know he's starred in musicals,but it really does work for the film.
The same applies to Russell Crowe and the rest of the cast. I loved Russell Crowe as Javert. I don't agree that his acting was poor.I love his expressions and body language in the film,which were perfect for his Javert.I loved him even more than HJ.
I loved almost all of the cast. The only blips for me were the Thenardiers.I'm still not convinced by them,though they had their moments,and I loathed MOTH. Also Eddie Redmayne annoyed me as Marius.He sings like a muppet,he really does,and he has some incredibly goofy expressions,much of the time when he's trying to look sad,with the exception of Empty Chairs,he looks half crazed.
Marius was a complete and utter goof in the book though so I guess it was appropriate casting.