This is a good movie if you can get past wanting to say, "Oh, I figured that out 5 minutes into the movie" Maybe not a stunningly original film, but still a good film nonetheless.
I felt the acting was excellent and the film was beautifully composed; the dream sequences in particular were suspenseful and eerie to watch. The carefully tended grounds of the main hospital contrast with minds of the patients and the decaying rust filled interior of the maximum security ward, an abandoned fort from the civil war, just like thel fantasies created by the patients in order to hide themselves from an ugly reality they cannot accept.
Is it better to live a monster or die a good man? Ponder that as you drive home from the film.