This allows the authors to adopt a more pragmatic style that favors 3rd party plugins. This is a good thing because IMHO the most important thing about a framework is it’s library of extensions.
Unfortunately this book was pushed out before symfony 1.3 was finished, and apparently before a sufficiently detail oriented proofer could go through the book. Luckily the issues are primarily non-technical and mostly limited to the first few chapters and should not deter you from purchasing the book.
The most notable technical issue I have with the book is the use of a XML schema instead of a YAML one, this actually works fine, it’s just a non-standard way of doing it. Also sometimes it feels like the authors did a search for 1.2 and replaced it with 1.3, again this is not that big a deal because the differences between the versions are mostly not relevant to beginner or intermediate symfony developers.
So would I recommend this book? Yes, especially if PAKT comes out with a second revision with better editing. This book provides valuable real world examples and accessible detail that eases the difficult learning curve of symfony development.