My only previous experience with The Princess Diaries is the movie adaptation, and I think I prefer it.

While the characters are the right age for this to be considered YA, it reads very young. I wouldn't hesitate to recommend this to its intended audience. It's a fun read, and Mia is a fun character to follow as she navigates being a teenager who suddenly finds out she is, in fact, royalty. There's definitely a lot of appropriate teenage drama when it comes to her family but also her friends, and I think the portrayal of the relationships, and how people can argue but still find their way back to each other, will be relatable. Mia is also someone who thinks protecting the environment is important. I can think of worse role models in books.

That said, I think I had certain expectations that were set by the movie adaptation. The way Mia's grandmother is portrayed here is vastly different, and I miss the kinder version portrayed by Julie Andrews, even though I can recognize that the book's version is more amusing. The book only tackles about the first third or half of the movie, so there isn't really much of a romance going on yet.

There are a couple of Arab characters whose names, as an Arab myself, made me wince a bit. Also saw a few of mentions of Israel that were completely unnecessary.