The ONT certification in my opinion was the best book I have read so far. Prior to reading this book I was honestly intimidated with QoS topics, but he made it easy to understand. I passed the exam today with 966 / 1000. I only have one mor to go ICSW before I get my CCNP Finished. The book is coming out on friday, i have it pre-ordered.
Also the practice questions that come with the CD in the book are actually quite good. I was surpised.