This is one of the most complex and compelling of Tarantino's films, and will appeal to his dyed-in-the-wool fans and also those interested in the subject it addresses - slavery. Django is the story of a runaway slave who was caught and punished. When the film starts he has been separated from his wife and sold, and is chained to other slaves being dragged across the frosty south. He becomes associated with a bounty hunter, played by Christopher Waltz who gives a spellbinding performance. Together they form a friendship which leads them on a quest to find Django's wife. There are frequent moments of black humour between them, reminiscent of Butch Cassidy and the Sundance Kid.
Along with his usual amount of splattered blood, Tarantino brings to the screen with amazing force the true horrors of black slavery, whilst sensitively building characters to bring these tortured people to life. Leonardo Di Caprio gives a chillingly friendly portrayal of Monsieur Candie - a slave trader involved in Mandingo fighting (two slaves fighting to the death). His appearance in the film changes the tone to one of overwhelming menace and racks up the tension.
The one criticism I have about the film is that Quentin Tarantino doesn't give a convincing performance in his cameo role. Quentin, stick to what you're good at, and leave the acting to those who can. :o)