My biggest problem with this book is very introductory level of the content. It feels almost like "abstract" or "index" of a sort. It points you to all the right directions, but leave you to explore them in depth by yourself. So if you have already worked with Spring Boot and Spring Cloud you will get almost nothing new from the book.
Having said that, for a new developer, who is indeed new to the topic, this book provides very nice overview of the field and puts your face into right direction.