Like most of the Blackwell anthologies I have experience with, this is very well put together and is a thorough (if not fully comprehensive) introduction to the most important and influential thinkers in aesthetics. I use it, along with some supplementary readings, in my aesthetics class, and focus there on the classical and modern readings - but I find it helpful that the book includes both a historical and a topical table of contents, so that you can read the selections chronologically or according to topics like "beauty" or "definitions of art" or "expression and emotion in the arts."
When it comes to contemporary aesthetics, this book covers a wide range of the most influential thinkers in English-speaking and analytic aesthetics, while almost completely ignoring the work of Continental thinkers (apart from a few selections from critical theory and hermeneutics, which is treated here as "historical" and not contemporary). The most glaring omission is that there is nothing here from Derrida, who did, after all, write a number of important and highly influential pieces on aesthetics (not to mention Deleuze, or Lyotard, or Baudrillard, or Ranciere...). Still, this is the most thorough text of its kind that I've seen and I wouldn't necessarily argue for omitting anything that is here in order to include those other things (since to do them justice would probably require another kind of book - best to consider this an "Anglo-American and Analytic Approaches to Aesthetics and their Historical Predecessors" anthology).
Another thing that would make it more helpful as a textbook would be to have a very brief introduction to each selection, outlining the issues and the central contributions made within the selection to the field of aesthetics. In my class I tend to assign readings first and then have lectures and discussions, and brief introductions would help to orient my students better before we meet to discuss. In lieu of that, I try to say something briefly before the reading, but it would be helpful for them to be able to turn back to the summaries during and after each reading, and it would be helpful for them to get a different take on the overall importance of the reading than I have to offer. There are broad essays introducing each period (e.g. a brief essay on "the classical period" - from Plato to Kant, and a brief essay on "modern theories" from Schiller to Gadamer), but that's not quite the same, and not as useful, as quick intros to each reading selection.