If you're looking for an action packed supernatural thriller that won't tax the the grey matter, this fits the bill. Aaron Eckhhart hams it up nicely as the "exorcist", and there are a few twists and turns to keep you on your toes.
It certainly warrants more than it's current rating, there are innumerable horror offerings that are much, much worse than this. Get the boys (or girls) round for a few drinks, and put this on. You'll easily keep up glancing at the screen in and amongst the conversation, and anything looks better with the aid of alcohol.