My girlfriend is obsessed with the horror genre so I literally have to see 90% of the horror movies that come out in theaters. I am not exaggerating. Killer puppets, killer mirrors, killer plants, serial killers, killer ghosts...I have endured them all. I do not like half of them but I get to see my action/gangster flicks with no complaints so it works.
This one was excellent. I hate movies that rely on loud surprises for the cheap scares (most horror movies these days). This one maintained a truly creepy atmosphere throughout and had me totally spooked. The "characters" were believable and by the end, I really believed for those two hours that i was watching home footage of a demon terrorizing a young couple. From a bitter cynic when it comes to the afterlife, this was a huge leap for me. I highly recomend.
By the way...DO NOT WATCH ANY TRAILERS OF THIS MOVIE IF IT IS NOT TOO LATE. It probably is since you are reading this thread but it will ruin some scenes.