Yeah, the film made the story pretty generic. It was still a gorgeous film, though, and fun to watch. I do recommend it, as an aside. I wish it had done better in the box office, so maybe we would have gotten an equally pretty sequel. Apparently the long, confusing name, and possibly the rather lackluster trailers, did it in.
The book series is definitely one to use caution when showing to children. It has some rather disturbing content, although mostly in line with what real owls will occasionally do. Aside from the mass brainwashing of small children, that's not really an owl thing.
Some kids will be fine with it, some won't, so it's best to read it over first. Which won't take you too long; it is, rather unfortunately, a series made up of fairly short books. Which is my main complaint, really, that I would like for there to be more of it.