With all of the positive reviews, I was excited to get this book. Unfortunately, I felt a bit disappointed by the content. First, a few nit-picky things. If you are going to charge $15 for a book, make sure someone other than yourself has checked for typographical and layout errors. While the errors I found after just a brief glance are not significant enough to impact use, it does diminish the overall quality of the book.
As for the content itself, a cursory view found some discrepencies between this book and the rules as presented in M20. The author acknowledges the differences between editions, but a bit more time comparing the sphere levels found in How Do You DO That and M20 appears to be needed. The lack of due diligence means that the purchaser is left having to do additional legwork to fix the sphere requirements.
The system presented for learning/creating rotes is unnecessary. The idea of rotes should not require the expediture of xp and M20 makes it clear taht rotes should never cost points to learn. The reason the base system in the book is so simple is because it is not meant to bog down the already complicated rules system in Mage.
Overall, the quality of content and layout is discordant with the price.