For this review, I'm assuming you have seen the movie (otherwise, why buy the dvd) and are considering owning a copy.
This is a fine DVD. It is not HD or Blue Ray, but it plays and looks great on my blue ray player.
There is really nothing wrong with the copy, and for that alone this would get 5 stars. But I rate dvds on their bonus material, especially the commentary, since this is where the added value is for me. And in this aspect, I think the value could be higher. The commentary was very half-assed. I don't mind the commentators goofing off or even digressing wildly - often this provides valuable insights into these personalities. But I expect a certain amount of discussion of the film, its production, the development of the story, the actors' interpretation of and improvisation with their roles, etc. The commentary section was very mediocre. Not bad, just not great. Hence 4 stars. If I was rating just the commentary, It'd be 2 stars.
The redeeming qualities come with the many other special features: the kids have a commentary track, and the kids have a video diary of the showing of School of Rock at the Toronto film festival; there is a fun music video of a song one of the kids (in the story line), and other such features. I found the kid stuff really fun. So many of them were so delightful in the film, it was great to get a sense of their real personalities.
Hope this helps.