I bought it for DD when we went on our last trip - she was 7. It is a really neat book, and she's an avid reader/writer. I thought that she would get more out of it than she did. There are places to write thoughts about attractions, and if you child hasn't been, it is a good way to introduce attractions. There are ratings for kids - "dark", "scary", etc., but the WDW for Kids By Kids has a similar approach.
Guide to the Magic also has places for signatures, and a section for around the WS at Epcot with stickers (colored like the country's flag). They can put the stickers for every country the visit as well as most of the attractions.
DD is 9, now, and I will find her sometimes with the book out and reading it.
It also can be used as an autograph book, but it is kind of big to drag around the parks.
Let me know if that answers your questions! (I might go grab it from DD's room and see if I missed anything...)
ETA: I have the book in front of me, and the other thing that I forgot to mention was the journal part. Remembering back, I think that I was hoping that she would get into the journal because I can't seem to! It has a place for the date, weather, temp, attractions visited, park(s) visited, transportation used, souvenirs, what/where I ate, favorite things, hidden Mickey's, etc.