I finished the game far cry 3-100% without needing official guide. For Far Cry 4, I do not think I need either. Why buy it then? For me it's more of a book where the gleaning some additional information. Eg for building weapons that you can buy, comparison is easier on some pages rather than having to juggle from one menu to the other in the game. Same for the manufacture of utensils (wallets, holster arms ...), in a table, was the summary of all the animals that will have cut up to obtain the various improvements. It also allows you to easily locate some places thanks to X and Y coordinates different places.
The structure of the guide is good. The humor is present (as in the game), the camps are faithful descriptions etc. I have already had some very poorly organized guides, without any additional information. Here I have found everything I looked for now.
I repeat, I do not need to finish the game, I "cheat" no. I do not have the book open on my knees by advancing in the game. But I like the flick from time to time to understand some of the subtleties (outside of my game phases). I use it as a guide-dictionary, not like walkthrough. And I am very satisfied.