I wrote a lengthy review that the website ate and I don't have the energy to redo it.
The short version is that previously published Taldor material was thin to the point that to set a game in Taldor you would have to basically create the nation from scratch. This book fixes that problem. If you want to run a game in Taldor it is essential, if you want to run a game in the Inner Sea where the PCs can go to Taldor it is very useful.
The scenario works reasonably well, but it feels rushed into publication. There are lots of typos, important details are missing in several cases, and some of the motivations and sections of railroad track don't quite make sense.
Good GM prep can overcome all of these obstacles, but the scenario would have benefited from another round of editing before being released.
That said there are some cool scenes once you hammer the thing into shape.