For me the book is a book of two halves. As you would expect half of it is about coaching Agile teams. In that you'll find that it covers similar ground to my own Changing Software Development: Learning to Become Agile - both are about introducing change. While I cover more management and background they cover more personal stuff.
The other half of the book is a nice, modern, discussion of how Agile teams work. Its not Scrum, Kanban, XP or any other method. It describes what you find. Its one of the best introductions to current Agile practices you'll find. Plus, it incorporates a lot of experience which earlier books couldn't.
One of the things I liked about this book is the "corner cases." This book covers those bits of the Agile development process which sometimes get skipped over. For example: the advice to keep your white boards mobile, something I always do but until now nobody has ever put it in a book.
There are lots of other great tips from two people who are in the trenches coding and helping people develop better software and systems.