1.There is a lot of unclear or loose description in the book. For example, The Shadow-Guard archetype is not limited to the blade-siren spell list, so what list should he use?
2.Some clsss features are too weak, but some clsss features are too powerful. And the class gain a similar rage ability in high level, but this class is not suitable for rage ability, it's too inharmonic with it's style!
3.Basically, almost every clsss feature should have a special abilities category, eg. Sp, Su, Ex. but in this book I did not see.
Unless there is a better revision later, or I do not recommend buying this book at the moment.