Can someone expand on why the book is so good? Its a practical overview of a difficult and modern topic. That in itself would make the book good, but for me, i

Can someone expand on why the book is so good? Its a practical overview of a difficult and modern topic. That in itself would make the book good, but for me, it is that the book goes deeper into the research and algorithms than most O'Reilly books -- but it does this without becoming a Science textbook. It is easy to tell the people working in big data that haven't read the book, just from the mistakes they make.