Reading it, I found it hard to imagine the book was written in the late 1990s. Despite occasional mentions of computers and video games, it feels like a book written decades ago. It has the feeling of a book that should have been a childrens classic for generations, despite it being only a few years old. She has a Dickensian or Vancian gift for names. The naming of names is one of the most important parts of literature, especially childrens literature.
Characterization is likewise sharp and memorable.
You know these people within minutes of 'meeting' them, and yet, they continue to shade and develop throughout the book. A few are never as developed as I'd like, but the author plans a seven book set, so I hope to learn more about some of the 'lesser' characters later. And, lastly, there was an attempt to tack on an 'extra' happy ending on top of the main one, which felt very forced to me. A running sub-plot in the book involved the competition between the various houses of Hogwarts Academy, with each house gaining or losing points based on the triumphs or failures of its members. At the very end of the book, Harry's 'house' is dead last, and the villainous House Slytherin is poised to triumph.