Okay, first a word of warning and a confession - the warning: If you're rather literal minded and analytical, you might not like this movie. I would say this movie focuses more on emotional aspects than rational ones. The confession: I read some of the other reviews here before posting mine, and I saw points in both the good and bad reviews.
The people who didn't like this seemed to have problems with questions left unanswered, things that didn't seem to make sense, and the mixture of an emotional drama with a ghost story, wanting it to be one or the other.
For those trying to figure out how the ghost can be this or that person, let's just say it was a demon impersonating all of them. Or something. The scares were still effective enough for me to be satisfying, and I can make up my own reasons for the apparitions with a little creativity. I can see why people had a problem with this, though. It is a little confusing if you linger on it.
Thankfully, for me at least, the story moved along and kept me engaged. The pacing was good. The scary parts were scary, and the emotional parts were emotional, and this movie did both better than a lot of movies I've seen lately. And yeah, it made me cry. I don't think I've ever seen a movie that's this effective at horror AND drama, so I definitely recommend giving it a try.