Well, I said it was decent, but when I compare it to Inglorious Basterds, which it's premise mirrored (Jews take revenge on Nazis, Slaves take revenge on Slave owners), it comes up short for me. It's just that I felt IB had an engrossing plot, several well-written memorable characters with a great climax and twist at the end. Django on the other hand had mostly one dimensional characters (Schultz was the exception, but it seemed he got the most attention from the screenwriter), a very linear plot, and the last half hour was a mess that knocked the air right out of it. After I heard the premise I was excited, and having seen it was a bit let down.
I read your comments about the music, and admittedly I am not that familiar with the genre, so perhaps I might have enjoyed it more if I was.