I think it was a really good anime!
I really appreciate the fact that they spent more time on the atmosphere and tried to deliver an overall creepy vibe (along with the mysterious plot that made you constantly wonder), instead of just throwing a bunch of blood and violence and calling it horror (yes, I know there was quite a bit of it but at the same time it wasn't the only thing that made this anime a horror anime- and that is what I liked about it).
Did not really like the later episodes as much as the first ones though, as they were not as creepy but still overall enjoyed the anime. I think there should be more "real" horror animes like that, there aren't enough in my opinion.