I won't rate a book I have contributed to because I am more than a little bit biased. Having said that, I do believe we have got some really good stuff in LESS!.
The book is really about breaking barriers, showing that the different movements who try to improve companies, Lean, Agile, Beyond Budgeting, Radical Management, Systems Thinking, complexity Thinking, and so on, have common ground. Together we can accomplish things none of us can do alone. We just need to get talking.
LESS! is a starting point. Software developers can buy it for the Agile stuff, managers for the management material, economists for the essays on budgeting, but when they do, they will get exposed to similar ideas in different communities. It is my hope that people will use the book as a conversation starter across organizational barriers.
Then again, you can just read it for fun. :-)