I have read all of the Harry Potter books and this movie is, by far, the most accurate.
I love the character development and the pacing of this film and I can't wait for the next one to wrap up the series.
Of course, I don't really recommend this movie for younger viewers - mostly because it is a slower pace than previous Harry Potter films. Also, there are some scary moments for children who might easily be scared.
If you haven't read the books or seen the previous movies, you are going to be lost. They don't play catchup in this installment. So take some time to check out the previous movies/books if you have the chance!
Overall - a fantastic movie with an amazing plot development. A must see for all HP fans!