In all honesty, I enjoyed it until Leonardo DiCaprio showed up. It was fun until then.
Christoph Waltz was being super sweet as always and it had the nice, fun feeling of any good Quentin Tarantino movie mixed in with the unreasonable amount of violence. That all changed when Leonardo DiCaprio showed up. It's certainly worth watching, I suppose. There are probably good reasons somewhere somehow that it beat Moonrise Kingdom for best original screenplay at the Oscars.
But it is just not enjoyable after Leonardo DiCaprio shows up. It's nothing about him as a person, but the things that his character does and all the tension and violence that is slightly unlike Mr. Tarantino in weird ways. Although it's true in the last half that there are some fun explosions, he takes it along a darker turn, and it stays that way until the end. So here is my advice; go see it, and if you're in the mood, watch it after Leonardo DiCaprio shows up. If not, you will be just fine with what you've seen before then.
I won't spoil the ending, but there's a general knowledge that the good guys win in the end. People rarely go into movies questioning if the heroes will turn out all right. And this is because they usually do. Django Unchained is worth watching, but watching the whole thing isn't really necessary.