Just another movie desperately trying to scrap some storyline off the cliche of nun horror by tarnishing the face of sisterhood and church leaders.
Of course the interesting point the movie makes is how fanatic obsession can lead to so much damage (which is true not only to religion, but also in secularism + anti-religion fanaticism).
I liked the the plot twist, but the story in general seems pointless to me, also exaggerated with unnecessary fear factor.