I think we have to be careful here. Many times I have found these kind of movies do more to bring the Church into question, or to serve as a source of ridicule. One has to really watch carefully and with some wisdom to not let the events in the movie bury what is really going on.
True, some things bring to the forefront basic practices of the Church and about the Faith in general, but I think they are minimal and incomplete. If a person is not well versed in the Faith they can be easily mislead.
Matters of the occult, possession and evil are dangerous things to delve into, and it is best to approach anything concerning them with a lot of prayer and caution. Than includes movies that are supposed to be based on real events. Perhaps most especially these types of movies. It is too easy to open the door to evil.
Following this; praying against the occult.