To begin with I have not read the book, and I can understand frustration when films aren't faithful to books, I hate that too.
I first saw this film when I was a kid and was enthralled by the atmosphere, characters and story and the memory stayed with me. I have seen it twice since then as an adult, and still love it.
I do understand worrying that it will scare children (and I certainly wouldn't show it to a 5 year old, it's not meant for small children) but I think that lots of children would love this film and parents should base it on their own knowledge of their children, most parents know roughly what their own kids will love and what they will find scary.
I've been trying to find a DVD of this but there isn't one :(