The payer guide is 'only' 12 pages, contains information about races with some recommendations, the 'book' gives you also some info on the starting point,but does not show very much information. The good thing is that the starting point of this adventure opens a path for practical every race or class to start. so there is not much info needed. However, only 3 stars because i like to dream ahead and some pictures or drawings from some hidden temple or old buried tombe would have made it more 'book'
I love the Faction Guide because it has 24 factions that hve different flavors. They endulge your players to add that flavor to their characters. Like the Kusari-Gama be all the monk that you can be and some more! and you get rewards! Players must love this. I think it should be a for both DM and PC.
For me? a must have to spice up a character.