The book itself is fine, but it seems not much care has gone into converting it to a PDF.
My two issues with the conversion are 1) unusable bookmarks and 2) missing pages. The bookmarks are a machine-generated mess of spelling errors and redundancy presented in one massive list of hundreds of titles. Needless to say they are unusable. Even more disappointingly, pages 29 and 30 are missing. Because of this, the introduction to the Flux Rating among other things are not included in this version of the book. It seems both of these issues would be very hard to miss with any effort put into QA.
It is sad to see the PDF sold in this state.