Fun trivia: the movie was filmed in 37 days. Originally scheduled filming for 39 days. That's pretty impressive.
I won't say anything more about the movie itself, 'cause if you haven't heard already, there's a "secret" and if it hasn't already been spoiled for you, I don't want to be the one that spoils it. Curses, Bill Maher, for spoiling it for me last week! I had been doing so well avoiding press about the movie. I have issues with some of the content, but it's a good movie and worth watching. Even if you don't like boxing.
ETA: An article at findlaw.com does a good job of spoiling the movie, if you're so inclined to know the ending without seeing the movie. The article also hits on one of my favorite aspects of law -- copyright law -- by asking the question: "The Controversy Over Politically-Motivated "Million Dollar Baby" Spoilers: Do They Violate Copyright Law By Destroying Market Demand For the Movie?" It's a good article.