Silly me for thinking that people wouldn't care about my opinion.
It's a great book. Some things could be better, of course, but it's a free book, so the quality to price ratio is off the charts, and not just because it's free. I would have happily paid $75 for it, maybe more.
That said, it's a book that requires you to care about the Linux kernel, where the author's experience is. If that's a problem, then you won't get as much out of it.
The book is best used as a reference after reading through it once. I would do a medium-deep read the first time. This will tell you the concepts you need to look up later, what techniques exist, etc.
This is because the book delves into detail about various techniques to get concurrency. The philosophy is to do the easiest thing that works, which is great, but it does mean it talks about details. Thus, it's best as a reference later after absorbing the surface level.
However, that medium-deep read is still necessary for you to know what you need to look for later when you need details.
