The book is filled with examples that explore the features in great detail. The writing style is casual enough for me without becoming too cheesy. That's just a personal preference, but I prefer my content blunt without any extra "entertainment" or an attempt at being funny. Grammar-wise the book was perfect and far better than you might expect from an average technical book.
I would say the book works very well as reference material and thanks to it I managed to understand several features, like
Mapand the weak variant, in greater detail. It's likely I won't find use for most of the features, but that's not the point. You get these ideas in your mind that might come in handy later. It's great to have the essentials in one place.
Note that you can read the book online. Also the source of the book is available.