I bought this book because I'm a big fan of Planet Cake and love their creations.
I think this book is an excellent purchase for the absolute beginner. The sections are organised by skill level, so you progress from simple round cakes, to square cakes, then to shapes and finally 3D carved cakes.
The cake designs are all abit basic (the most complex is the one featured on the front cover) so an experienced decorator looking for some inspiration or looking to learn new or complicated techniques won't get alot of use out of this book.
Aside from that, it gives a beginner really useful tips for their decorating, for example, repairing fondant or applying glazes to give a shiny finish to fondant.
I've been decorating cakes for awhile now, so I don't think it gave me anything new, but the instructions are great and really detailed, there are a few new recipes you don't get in every cake book (I love the white chocolate mudcake and the flourless orange and almond cake recipe) and it was great to have the cake instructions broken down to see how Planet Cake achieve their spectacular cakes.