Yes, I bought this book after getting the free e-book copy and reading a lot of it but this book is so good and thorough that I wanted my own physical copy in addition to the e-book. When e-books were introduced, I had visions of eliminating my wall of books in my home and going to work with only an e-book reader under arm. Alas, so far that hasn't happened yet but this book, I'll carry until I master programming in Silverlight for the Windows Phone 7. I've purchased other books on Windows Phone 7 programming but this one has proven to be the best. It is enjoyable to read the insights that are shared and to ponder the example programs (over 100).
Pro's: Very thorough step-by-step discussions of each topic with many illustrations. Covers all topics that a developer needs including architecture, use of Visual Studio 2010 and deployment to the emulator in Visual Studio 2010 or to an actual phone device. I particularly like the author's opinions and speculations about the future directions that Microsoft might take that he inserts for the reader to consider. Also, Microsoft Press books seem to me to be more error free than many others.
Con's: No end-of-chapter questions or glossary of terms. This is actually a plus for me since I am writing my own multiple choice questions as I read the chapters. It is helpful to look back at a chapter and try to identify the most important concepts related in the chapter and then to formulate good questions and answers that differentiate clearly the key information presented from other answers that sound good but are not correct. Sadly, most technical books these days don't include end-of-chapter questions and/or a glossary so the reader's (especially me) often find themselves reading along with the feeling that they "get it" but in a later chapter, suddenly discover that they are lost and don't know what chapter to return to, in order to get back on track.
I've only chosen one other time to write end-of-chapter questions for one other book that I also wanted to master. I wrote over 750 questions for Jeffrey Richter's "CLR via C#" (2nd edition)) because this is another of the few authors and topics that I felt strongly, deserved mastery, not just familiarization.
If the book is by Petzold (or Richter or a few others) I usually want to purchase it with little hesitation as these authors never disappoint me. If anything, I am usually in awe of their tremendous knowledge and ability to craft it into a great book!
BTW: Amazon notified me that they are sending me a check for a little over a dollar because the book price went down after I ordered it. Cool!