Personally, I like his book. I’m not a beginner, and I’m certainly not going to take everything he says at face value. He explains many concepts very well, and the errors in his book won’t cause his audience to do really big screw-ups.
The depth-of-field quote… it’s correct for some conditions, wrong for others. But it has the benefit of getting beginner photographers to at least think about depth-of-field. He suggests using f/22 for its great depth-of-field, and he minimizes the diffraction effects. Well, I may disagree with him, but I’ve done tests that tell me when f/22 is usable and will be good, and when I should avoid going there. If someone uses f/22 and gets a great image with depth-of-field that is slightly soft due to diffraction effects, no big deal.
He suggests using “cloudy” setting to warm up the pictures. That’s a personal preference. He suggested using the “tungsten” setting to get really deep blues… also something worth experimenting with to decide if it works for you.
As for factual errors – all books have them, including textbooks. No news there. I’m willing to bet that when we compare internet information, we’ll find many more mistakes… But most people know to take what they find on the internet with a grain of salt.
My opinion, for what it is worth, is that the book does more good than harm, and if the average photographer takes the information it presents and uses it intelligently (ie, with some experimentation of each concept), then it will certainly advance their skills.