In today's economy, customers buying books need to know exactly what they're buying. In this case, what your thirty bucks buys is -- apart from the previously published text (the novel itself) and the previously published art (interior art) -- is, essentially, a new cover by longtime Harry Potter cover artist Mary GrandPre, and a black-and-white illustration by Rowling (quite the cartoonist!), which comprises the "bonus" material Scholastic has been touting but keeping under wraps.
The wraps are off and, while the illustration is nice, Scholastic would be better off issuing either an illustration edition with more art (which, by the way, exists), or taking the momentous occasion of the 10th anniversary to celebrate it in a significant fashion: Rowling, why wasn't there an original interview in which you looked back at the ten years of Harry Potter in the media? Why wasn't there a long essay by a respected literary critic looking at the Harry Potter phenomenon? Why wasn't there MORE text?
If this was simply a reprint edition, the omission of new text would be understandable. But when you're celebrating ten years of Harry Potter in print, how, exactly, does a new cover, a previously published (to the best of my knowledge) illustration for the colored endpapers, and a black-and-white illustration by Rowling "celebrate" the book's publication?
As there is no historical retrospective here, I'd have to say that Scholastic missed the boat: This edition could have been so much more, but it suffers (ironically) from a failure of imagination.
I have rated it five stars because the first novel is a literary classic in the children's field. The publisher, however, needs to think about how to ADD VALUE to the existing edition when touting its "anniversary" status, esp. if they intend on reissuing matching volumes in the future. Otherwise, it comes off as being just another edition to get the fans' hard-earned money, instead of offering something new, different, and significantly improved.