A friend and her husband went to see City of Bones when it was in theaters a while back. She was going to read the book, she bought it - but she decided to just see the movie anyways. I watched the movie once it came out on video. I liked the movie. She didn't. I understood the movie, I knew the back story, I knew what why things were happening the way they did. She didn't. She didn't get it.
This is the last book of the series. And I gotta say, I really liked how the author brought all the books together (including the Infernal Devices series, sort of a preseries trilogy to the Mortal Instruments 6 books series.) I liked that she still brought in new characters even though the series was ending. I liked how she brought in characters we had read about a few books back. I like the ending she choose. I like the resolutions that took place. I finished satisfied. And what more can you ask for when reading a book series?
Now, they are all written, they are all published, they are all available. I'd say read books 1-5, then through in the Infernal Devices trilogy, and then wrap it all up with this one. They are very long books, as in, they have a lot of pages - just like the Harry Potter series. But like the Harry Potter series, though this is definitely for an older crowd... well, I suppose an older crowd was the majority of the readers of the HP series, that series is also kid friendly, or can grow up with kids reading for their years. This one is for teens at the youngest, but late teens probably and older.
Enjoy them all!