I tried reading the first one and got as far as about Chapter 6 before thinking to myself, "This is sub-standard Roald Dahl."
I agree they make good stories to be made into what used to be called a family film, but I\'m not convinced they are particularly great works of literature. If you want good fiction for teenagers (and adults), check out G.P. Taylor\'s Shadowmancer or Phillip Pullman\'s Dark Materials Trilogy - far more satisfying.