The gist of this is if you get a chance, go see Possessed. Just go, it's a great film.
And for those of you who don't just take my word for it (what the hell is wrong with you?) I've typed up an actual review...
If you like horror films, and I don't just mean the splatter gore porn, I mean real creeping dread then Possessed is the movie for you. It's all about atmosphere and character -- something sorely lacking in what passes for horror in America. This is like those '70s classics -- The Exorcist and The Omen -- all about the slow build into the horrifying finale. Except, and this is a big plus to Possessed, it lacks the cultural trappings of that era, making it so much more real and familiar even to a foreign audience.
And if that's not enough to sell you, Possessed also offers up an excellent critique of religion in daily life. Not theory, not rhetoric, just how everyday people adapt these beliefs and stories to their own circumstances. I'm being deliberately vague because I don't want to spoil anything but suffice to say this movie illustrates parallels between two very different faiths and it's far from flattering.
So yeah, go see Possessed. Old school horror done right, not like that fruitloop hack Miike.