Overall, I would say that it was helpful and recommend it, but even though my copy was a first edition, it did seem like the book contained way too may typos (both grammatical and in the ActionScript itself). Typos aside, the chapters on the Display List and XML were both extremely concise and informative. If you’re unfamiliar with either, I’d recommend giving them a look.
Like the other books in O’Reilly’s Cookbook series, the ActionScript 3.0 Cookbook works as a quick reference to commonly encountered problems. Focusing on the end results, their problem/solution approach to education works well when you’re already somewhat familiar with their subject.