Framing Story: Actually very interesting and well-written, though since it's been forever since I started the book, I was a little unclear at the end as to exactly what promise Marina had extracted from the sidhe at the beginning.
History: Good coverage, but significant overlap with pretty much every other Changeling sourcebook I've read so far. The people & places bit was interesting, though.
Mechanics: See above. Some of the new stuff is intriguing, particularly the shape-shifting bits. I might consider delving further into those if I decide to build an eshu next iteration. The archetypes were really cool, too, and the piskies were a good addition, even if I'm a bit lukewarm on the spriggans. I mean, what would a seelie spriggan do besides not steal babies?
Gamemaster's section: SPECTACULAR. Elevated this book from 3 to 4 stars. Gives great plot hooks, and the whole blue book idea is excellent. Highly recommended.