I thought it was brilliant. Certainly the first half of the film is absolutely stellar, and its a lot of fun seeing Django dishing out vengeance/justice to all the slavers. My only contention would be with the switch to DiCaprio's slave ranch and everything that happens there- although DiCaprio's great it feels like the film slows down a lot when it gets there.
Sterling performances from all (except a director cameo which sticks out like a sore thumb but does have a crowd pleasing death) but especially Christoph Waltz and Samuel l Jackson. Jackson in particular is going all in here for the first time in a while.
Agreed on the performances - Samuel L Jackson is particularly brilliant, its unusual to see him in such a complex role. Even the QT cameo didn't bother me too much.
Speaking of which, since I don't think its posted here's a funny video of his getting annoyed by Channel 4's Krishnan Guru-Murthy: http://www.youtube.com/watch?v=u7ER_q0B1-I