On the one hand, they do not shy away from l'Divine Marquis' depravity, nor the notion that his work was unprintable. They danced around the idea that he wrote specifically to be unread. Rather, they had his writing as a compulsion. Also, the way they made the villain (Michael Cain) a despicable hypocrite is a great addition.
On the other hand, I don't like that Sade wanted to make sure Kate Winslet's character was buried in a Christian fashion, and they kept his arguments with the priest (Joaquin Phoenix) to a minimum. But actually, these could be looked at in a different light.
Sade was a devout Atheist; aside from that we do not know what he really thought about much. His was a life of satire and parody; also a life devoted to pissing off those he hated. With this in mind, you have to be careful with what you think Sade means by his writing. For example, in most of his books there is a severe hatred for mothers. All of his major characters (aside from Justine) hate their mothers. Sade, however, in a letter to his stepson said the boy should cherish and love his mother. A desire to gain points with her or shut the boy up is a possibility, but as it is a personal correspondence he might be speaking his true beliefs.
Lockwood mentioned he "remember[s] coming away with more empathy for de Sade." This is likely the best part of the film, and one I initially missed, as I already loved the man. The Marquis de Sade spent roughly twenty-six of his seventy-four years imprisoned. He was imprisoned by King Louis XVI, Robespierre's Revolutionary government, and by Napoleon. That was nearly 35% of his lifetime, and his imprisonment was not due to any crime other than embarrassing his mother-in-law and being seen as immoral for his writings. The few violent and/or harmful crimes he was accused of found him either acquitted or pardoned. You can imagine him wanting to lash out.
So, as a Sade enthusiast, I do recommend this movie. It is not a completely accurate biography, to the best of my knowledge, but I feel it is an accurate dramatization of his life at the time. The main lacking is in the shadowing of his intelligence. He was a brilliant man with a great mind. His compulsion to write is, perhaps, accurate. Sade refused to buckle, even if offered freedom. Ultimately his philosophy might be boiled down as "to thine own self be true." Therefore, I do recommend the film to those uninitiated and interested. It streams on Netflix, and you can see some clips at Hulu.