Short story: If you want to work as a game programmer in the industry, you absolutely should understand the information in this book 100%. However, it is truly an advanced book, and if you are just getting into C++ usage, this should probably be your second or third book (at least).
Long story: There are few textbooks required by the Digipen Institute, one of the best game programming schools in the country. It emphasizes working together with your classmates to actually learn how to create games, so there is not a lot of actual book work to be done. This is one of those few books required. That alone should be enough to convince you it is worthwhile.
Let's go into a bit further though. The game industry has been alive for decades now, and that has led to standards and styles of programming that proves more effective than other methods. It is accepted that C++, and object-oriented programming in general, is the way to go. Event-driven programming is common in large titles. Resource management is a common theme in a game with gigs of data that needs to be continually streamed in. Multiple controller schemes need to be supported.
The authors of this book have worked in the industry, and this book is their offering to help teach you how modern games are made. Other books will manually load in individual resources, or will read the state of the keyboard directly in their examples. This is fine when you are first learning DirectX, for instance. But if you plan to work with a team, and you have tens of thousands of lines of code to debug, much of which you may not have actually written yourself, you need a better structure supporting your game, or it will become top-heavy and impossible to finish. This is what they are focusing on getting across.
As good as the book is, even more valuable is the sample game that has been built and evolved since the first edition of this book. Teapot Wars is freely available on Google Code, and it is a working example of everything they are trying to get across. It actually has more complex examples of the topics discussed in the book, and internally it is a basic version of a AAA title. Understand its structure and you will have a massive leg up in your quest to become a game programmer.
So this should be the book to buy right? Just understand it and you will be good to go, right?
Well.... yes and no. This book assumes several things, without really saying them outright. It assumes you have proficiency in object-oriented programming, especially in C++ programming. They assume you are comfortable with the concepts of inheritance, using abstract interface classes, overloading, encapsulation, and all those fun names you see thrown around in the Wikipedia definition of OOP. They build some fairly complex abstract factories and just throw them at you in the book. It took me months upon months of carefully reading C++ books and going through their code to finally really start to get it. I bought this book right when it came out, and I only now feel comfortable to write this review.
So this absolutely should NOT be your first book. You must study OOP and C++ first. Another book that Digipen uses, C++ for Game Programmers by Noel Llopis, may be a good start. I went through Thinking in C++ by Bruce Eckel years ago, as it is freely available online, and it's a great start too.
This book uses the DXUT framework, which has been deprecated by Microsoft and stripped from their MSDN online documentation. No big deal, it still works fine, but the main function may seem tricky to you because of it. They do not use DirectInput which is good, as Microsoft is no longer supporting it and it doesn't seem to work in 64-bit code. It assumes you understand how DirectX works when you get to the graphics chapters, so understanding the graphics pipeline is a good idea.
So you see, this is not the kind of book that says it's the only resource you need. In fact, it's probably the third or fourth resource you probably need. There's a steep learning curve, though kudos are due to the authors for being extremely available on their forum at [...] Seriously, they respond within 24 hours to any question anyone has.
However, if you understand everything in this book (a process that could easily take a year or more), you will have a clear idea of how a modern AAA game is created. It's just a framework, but you will probably be ready to start taking on major game programming projects. And that is a compliment that no other book on the market likely can boast of.
So in conclusion, I think any budding game programming will be doing themselves a HUGE advantage by making sure they understand everything this book is talking about. It is the more Complete book I have ever read on game programming, and is 100% essential to anyone taking themselves seriously. Just make sure you understanding object-oriented programming in and out before you begin, or you will be very lost very quickly.