I don't have the book. Please keep that in mind.
However, I was already skeptical, and I'm reading a lot of people that are generally pretty sure of Paizo's ability to produce good material finding some issues with Ultimate Magic.
Ignoring the people that went ballistic over Paizo not fixing things that they hated since 3.0, I've not see quite so much wide ranging concern on the message boards in a while.
I won't go into some of the issues brought up, because I've not directly seen them myself, but I really do hope that this content ends up in the PRD soon so that I can evaluate it for myself. Hopefully I'll be pleasantly surprised.