When we first got WYSIWYG and desktop publishing people would say "Anyone can do it" and leave out the last word, "badly".
The primary limitation of this book is that it tells you how to use a (brilliant) program to typeset documents. In that sense it is a very good piece of work. The writing is clear, concise and humorous. The author is self evidently an expert in three fields (typesetting, coding and explaining). He leads you through many areas of deep knowledge so you know the how and why of what you're doing. And if you work through all the exercises, you will be good at what you do. Unmatched actually.
Implicit in this is the readers have an eye for beauty (this is about producing beautiful, readable text after all), but how many people do? Knuth tells us everything we need to know about how to spot beautiful typesetting, but this is a different skill, and I know from experience that a badly laid out TeX document is as bad as any MS Word document.
So this book wont give you that skill. If you don't have the eye, you'll be competent, not exceptional (but TeX has good defaults, so it may not effect you).
But the book has other levels. If you find yourself having to develop a Domain Specific Language then TeX is the primary example of a big DSL and the disciplin needed. It demonstrates many principles, but the key one is that you can't just capture a process and throw code at it. An excellent result needs both knowledge of how to code, why to code and what to code.
The third level is that this is a manual that demonstrates very clearly what a manual can be like. The dry-as-dust appraoch you see in many vendors manuals makes them difficult to read, provide skills without insight, and re-create the a world where 'Anyone can do it, badly'.
So, 5 stars.