The rules themselves are fantastic, and the sailing system is the best I've seen.
But the reason I rate this product as 1/5 stars is because this PDF book is a scanned copy, and the scan quality is very bad. The text is very blurry, and I strongly urge you to take a look at the preview before deciding whether or not to make the purchase.
I still went ahead and bought it because it's very difficult to get hold of the physical book these days.
[1 of 5 Stars!]