We're just back from the movie. My 9 year old daughter and I went together. I actually thought that it was far, far less dark than the prequels, which to me were really just a long drawn out story of one dude's descent into madness. But maybe that's because JJ Abrams does such a great job with inserting humor into the movie? I dunno. My almost 6 year old was scared to go without someone vetting it first (he doesn't like new stuff), but I think he would have been OK.
I now have a lady crush on Oscar Isaac.