Well in my knowledge brush up for 70-431 Exam I used this book backed up by BOL.
If you have previous SQL Server experience this book and BOL is all you really need to pass the Exam.
If you're a newbie who is just getting it's feet wet then first get some experience and comfortability with SQL server first.
The book is a very easy read and although it has some errors they're not huge so i didn't need errata (fixed errors) for it.
It nicly summarizes the topics that you need to know about and the chapters are just long enough.
Content fits very nicly with the exam itself. It doesn't get too techical if it doesn't need to be.
I liked the "Note" and "Exam alert" paragraphs throughout the book that warn you about what you need to study more in depth.
Each chapter ends with practice questions and their answers with full explanation of why it's a correct one and where to look in the book for more info.
The book also contains 2 practice exams with 40 questions each that are on the same level as those on the exam.
All in all i can't really say anything negative about the book. It serves it's purpose well. And that's it.
You can't really keep it as a reference or anything like that because it's to general.
Amazon link here.