Nice, very solid and pretty GM screen, the strudiest I've seen so far. It's also one of the few Pathfinder products whose italian translation wasn't grossly mishandled by Wyrd Ed. Not 5 five stars only because of some tables that aren't necessary but are there in place of other ones, and because I would have loved original artwork and not just a reprint of the iconics.
Wheter you want to have a goblin PC, flesh out goblins as villains a little bit more, or start your own all-goblin campaign, this book is what you need. It has interesting insights into Golarion goblin culture and tribes, along with various player options. It motivates you to use the annoying little freaks as PCs: we are currently running an all goblin pbp adventure on this board and having a blast.
I have only 1 minor complaint about the editing (a paragraph of the wrong font size in the Feats section) but overall the print quality is very good. A must have if you like monster player races or just can't get enough of those lovable pyromaniac goblins.