We're having a Harry Potter moment at our house. Younger Daughter has been watching the movies obsessively, and Sainted Husband read books 1 and 2 out loud to the whole family. Older Daughter has been plowing through the books.
Book 1, Harry Potter and the Sorcerer's Stone, is charming and fun. It deserved to be a best seller. Rowling's strengths are her sense of humor and perfectly realized wizarding world. The book isn't especially original -- it's clearly in the tradition of British boarding-school stories -- but it was well done.
Book 2 was also quite good, but starting with Book 3 it all started to go downhill.
Rowling's weakness is that she's basically very conventional. She's accepting of all kinds of stereotypes that I would like to see her overcome. Would it have killed her to make the lead character a girl, for instance? Did she really have to make the Dursleys so loathsome? I was worried about my adopted daughter being exposed to these images of abusive adoptive parents. I wish Rowling would ditch the weight stereotypes -- fat people are self-indulgent and lazy (the Dursleys), and skinny people are active and good (Harry).
Rowling is very British in her attempts to have the birth issue both ways. On the one hand, she deplores the wizards' prejudice against "mudbloods" (those with no magical parents.) On the other hand, every quality Harry has is traced back to his birth parents, or more precisely his father. (Again, would it have killed her to make Harry's mother a more interesting and vital character?)
There were times in some of the later books where the story gets completely bogged down in the adventures of Harry's parents' generation. Hint to Rowling -- that could be a separate series.
In the later books, Rowling attempts to get deep by killing off her characters. It doesn't work. Also, she deals with Harry's adolescence by making him angry all the time. The books are a lot less fun as a result.
By Book 7, it was all out of control. Get that writer an editor STAT! Book 7 could be cut to 1/3 of its present length, and be a much better book for it. The question everyone was asking before Book 7 was published was -- will Harry live or die? Rowling had him do both! Please, just make a decision. Also, I found the coda, which describes Harry and Ron putting their own children on the train to Hogwarts, unbearably banal and suburban. Couldn't they be out chasing dragons or something?