I read it and didn’t regret it. The ordering is interesting (human, natural, material, and territorial realm), and the kanji radicals and kanji that are hieroglyphs are nicely visualized. Some of them could probably be contested and are explained differently somewhere else, but they give interesting ideas on how to interpret the roots of a kanji.
But for the compound kanji it seems to me like WK’s approach with different radical names. There is no real explanation why components are combined, or the book just explains the current form although the kanji form was altered. For example, the book can give the impression that some kanji created 70–80 years ago during the script reforms have some etymological significance.
If you want some real etymologies beyond the hieroglyphs you have to look somewhere else, but this one is in English and 20 dollars for 650 pages are an OK price.
One thing with the PDF is that it doesn’t have hyperlinks inside, so the physical book is superior if you actually want to reference something instead of going through it from front to back.