There are definitely quite a few errors in this book. However, it does not deserve the low ratings it has. I wouldn't hesitate to recommend this book to anyone. It should be noted that on the very last page, the author explicitly acknowledges that there are "intentional" flaws that the author left in the widget game, but doesn't say what they are... Perhaps the people complaining about the errors didn't even read the whole book? Anyways, the author should have pointed out where the mistakes are in the book as she put them in. At a couple points, complete sections of code were missing... and there were plenty of typos. I wonder if the author just said there were intentional errors at the end to excuse the poor proofreading? Despite all the errors, the book is still great; not excellent, but great. The errors are all minor. If you can't figure them out, you should probably find another career because you are bound to make tons of errors as a programmer/game developer.
My only complaint is that it didn't go in to more detail on certain things, but then again, this is an introductory book. It should be noted that this book is written for unity3d version 2.x, but it will work for 3.x. The only difference is a couple menu options are changed when viewing specific things. I wish there were more books on unity3d that were up to date and went in to more depth on all aspects of the engine. I'm not aware of any "advanced" unity3d books that are out yet, at least at the time I'm writing this. Considering how few books there on unity at the time of this writing, the author should be applauded for her contribution.