The PDF is of really good quality. To be honest (no offence to you, the author), I was expecting yet another 15-page piece of crap where you have to pay to get the "real" lesson. But no. Almost 200 pages.
I can recommend it to beginners / intermediate level. They'll learn a lot. Perhaps a little less useful for those who already have some experience. However, it's a fine piece of work.
(and for those who are afraid of receiving advertising in the future, take a temporary email for 10 minutes / 1 hour like you can find hundreds for free on google, a fake name and that's it.).
Thank you for this quality PDF !