Difficult for me to read in French but well worth the effort. I also have the book in English and, whilst it is a sweeping, magnificent tale, the beauty of Victor Hugo's french prose wins out every time. If you can read some French, give it a try - his style is pure and uncomplicated (although very long sentences sometimes!) and you maybe surprised to find that you are not looking up the words too often.
As for the story - it tells of human nature at its worst but also at its best.
I read this novel many years ago when I was a student, (in French). Reading it again now - in French - I have enjoyed it more than I did then, probably because there was no examination pressure this time!! Even for a French native reader this will be considered a long ramble! The French language is impeccable, but an understanding of the political scene after the revolution is essential if a clear understanding is desired. The musical version - which I have not seen - must only have taken the bare bones of the narrative along with its colourful characters as its basis.
Translations are often fine and an English film of a classic are usually satisfying but it is great to go to its true source.. It is a while since I used French in a big way but am enjoying the reawakening.