My parents showed me a lot of films young and this was likely my favorite film when I was about eight. It didn't disturb me too much and I still like it now. I think younger kids can watch it, they wouldn't understand the messages, it won't be harmful to your child.
I loved Eternal Sunshine of the Spotless Mind, so I thought I might as well check it out since it's by some of the same people. Unfortunately, I didn't like this one nearly as much. It deserves credit for being clever and original, and it has a couple of brilliant surreal scenes, but something about Being John Malkovich rubbed me the wrong way. All the characters were despicable and real creepy, and the whole movie was so cynical and bizarre that it soon became a little tiresome. Interesting, but not a very enjoyable film. I'd recommend Eternal Sunshine instead.