The book is very interesting to know the different implementations and the challenges faced by the developers implementing these kind of software (info distribution strategies, transactions, replication, and so on).
Personally, although the book helped me to remember certain concepts and learn new ones, it was not exactly the kind of content that I was expecting.
The book in general is interesting, but perhaps is more useful if you are working creating a database or something similar. For the enterprise application developer or for a system developer, although the book is interesting, it won’t add too much value.
In summary, good book if you are designing / developing infrastructure code to deal with state (distributed log, database, broker, etc).