This is a short book of small best practices and tips that can help prevent big problems in production or poor design choices. I recommend that anyone building applications with Akka finds aroud 20 minutes a day to read through Effective Akka which would see them complete it in around 2 weeks.
Upon completion of the book you will have absorbed some of the knowledge picked up by Jamie Allen, of Typesafe, that was gained during his 3 or 4 years of building large-scale Akka applications.
Short Book, Short Review
The book is short, so this review is short, but I will give you an example of two of my favourite tips. The first is to use a separate execution context for actors and futures. You don't want futures starving actors of CPU time, which is exactly what this tip prevents. The next tip is to use specific messages - i.e. don't share them. I've seen the problems with this first-hand where it can be hard to work out what is happening because the same message appears in a few places.
Aside from the content of the book the style and quality is of a good level. There are no typos, the text flows well, and importantly the code examples do a fine job of highlighting the point the author is trying to make.
Effective Akka is short on content but big on value for anyone building systems with Akka.