The real draw for many readers will be Pastis' illustrations, which are similar in style to his Pearls Before Swine comic strips. This is one series that my students who won't read anything but Wimpy Kid books have been eagerly checking out.
While not a personal favorite of mine (IS the polar bear real? Seriously, this is a big problem for me! Plus, the weird names always bug me.), this series is a great addition to the list of middle grade Notebook Novels that includes Berger's Lyttle Lies, Tashjian's Einstein the Hamster books, and Ignatow's Popularity Papers.