Just saw it with my German friends, and it wasn't horrifyingly awkward; they really enjoyed it, but said Brad Pitt's accent was very difficult to understand.
I thought it was great. And the bit with the three fingers at the bar was a total mindfuck because I learned about that in German 1 but totally forgot about it. I really liked the fact that the majority of the movie wasn't in English. And the fact that the characters were multilingual really created some tense and hilarious scenes.
I was one of only maybe ten or so people in the entire theater who laughed (nervously) when Landa started speaking Italian to Aldo. I love the jokes that exist merely by the use of the language.
And Christoph Waltz deserves a fucking Best Actor win.