Basically, the original is SO MUCH BETTER than the new movie. Honestly, after watching the original cast, Crowe and Hathaway were no competition whatsoever. Since most people are already familiar with the storyline and plot, I won't really go into much. However, I will say that I greatly prefer to watch Les Misrables than try to read it. Between you and me, the book makes for some incredibly slow reading. I actually never liked the plot-line that much; I mostly just want to smack Marius and his girlfriend. I mean, I'm a great supporter of "true love," but sometimes there are other things more important than your love life. At the same I feel like the leaders of the rebellion are supporting manipulating people into mobs, which I don't support. When a situation is bad enough to fight for, people should want to join together without needing to be raised into a frenzy first. Then there is the whole Valjean/Javert situation--the concept that one guard would go nuts because some ex-prisoner didn't check in for parole is a little sketchy. And it just goes on and on. Long story short (see what I did there?), I don't really like the actual story.
What I do love about the musical is the music. The original cast did an amazing job with the songs and dances -- I actually heard "I Dreamed a Dream" in a Chinese karoke bar one summer. I have most of the songs my playlist, especially "Who am I," "A Little Drop of Rain," and "One Day More." So even if you can't watch the play, pick up a copy of the soundtrack!