Got a hold of this one over Christmas Break and plowed through it pretty quickly. A lot of it is Juul's notes and lectures from the past year on casual games compiled into a solid reference. Not all of it was totally relevant to the topic at hand, the latter portion of the book was breakdown of how match 3 games have evolved over the years which is to say they haven't really changed all that much.
The best parts of the book are when Juul gets into solid analysis of the different variations of the casual genre and interviewing their creators to see what they were thinking when they made them. He also gets rid of a lot of bad misconceptions about casual games like the notion that they are supposed to be easy or lack a fail state. As he points out in the book, the last level of Zuma will kick your ass no matter who you are. The same goes for a lot of other matching games.
Interesting book, it got me to start looking harder at the stuff over at Popcap and take a lot of Zynga games more seriously.