J.K. Rowling brought me to the story, the story and message kept me reading.
I have read the first two Harry Potter books with my 6 and 4 year old, and we decided to take a little break from HP and read the Christmas Pig since it just came out and it was the Holiday Season. I will say, the first few chapters were a little intense for my 6 and 4 year old, and I did, throughout the story, make a few minor adjustments to word selection to make it a tad more appropriate for the vocabulary I want my children using. However, once we got passed those first few chapters, the story blossomed in to a journey through our emotions. My four year old was brought to tears in a few parts of the story both from sadness and happiness. They both had questions and theories about what was going to happen. They were engaged the entire book and always wanted me to keep reading.
I can understand and see some of the points others have made in low review scores, but I'm so glad I read on after the first few chapters. I would rather those topics come up while my wife and I are reading a story to them so they can ask questions in a safe environment rather than learn it elsewhere. Each of those "bad" moments in the story can be turned in to a great learning moment where you can explain to them why someone did what they did and how they could have possibly responded differently. I would suggest to keep reading if your on these sites trying to decide what to do. However, you know your kids best and what they can and can't handle.