When I say that Don't be Afraid of the Dark is one of the scariest movies I've ever seen, I don't mean it as a good thing. Not that I have anything against scary movies. Signs, when I first saw it, was pretty scary and is still one of my favorite movies of all time (back when M. Night Shymalan was making interesting movies and not the stuff he's done recently). When I say that Don't be Afraid of the Dark is frightening, I mean excessively so.
Signs sort of eased you into things. It had some scary moments scattered here and there, but they were brief, and it wasn't until the very end that things got really terrifying. By that moment you cared about the characters so much that you wanted to stick with them, through the horror, until they made it out alive. This movie, on the other hand, it quite terrifying from the get go. The little creatures that serve as the primary antagonists are really creepy, and they are not afraid to use creative means of capturing and or killing their target.
It doesn't help that their target is a little girl. Sure, I know Signs had a little girl, but at least the adults around her were competant. They didn't believe the strange stuff right away, but when they were forced to face the facts they reacted by taking drastic measures to fight back.
In this movie the adults continue to go about things normally, even when they've accepted the danger, and this defenseless little girl continues to get attacked by these creatures, over and over again. Such scenes are so terrifying that they're disturbing. The movie makes an effort to get you to care about the characters, but when everyone is so blind to what's going on...except Kim...it made me want to walk out of the theatre when they got attacked and were helpless to defend themselves. Even the little girl, when she hears voices coming from the basement, goes and tries to make friends, instead of getting scared. By the time she is scared it's too late. The creatures are out and they're after her.