Well, I already blogged about it, but it really is surprisingly good. I totally agree that the monster thing is stupid - but I've not heard much about that. I expect it's because the last movie like this from the director (as producer) was Cloverfield, in which the monster was a) the whole point of the movie, and b) really unscary and silly looking.

But really, the monster doesn't matter - it's the kids and their relationships that lift this from triviality to engaging, perhaps even moving.