For me Maguire had a lot to live up to. Wicked was sensational, and Son of a Witch continued his story of Oz perfectly. Yet another new take on the adventures in Oz we thought we knew.
In truth I was dubious about a tale of the Cowardly Lion. Always the least favourite of the characters in my opinion, Maguire had a challenge on his hands to pull this off. And he does. Kind of.
Oz is at war, the political backdrops are classic Maguire, and his development and reveal of what we assume are stage-side characters blossom at a perfect pace - it made me want to keep reading! The two protagonists, Brrr the Lion and Yackle (the previously discrete oracle hag) grew to be more appealing, interweaving their stories in interviews. There is tension, drama and that level of humour we have grown to love in the previous novels. Brrr is endearing to an extent but one can see where Maguire has tried to make him so. His adventures were a tad dull, but I suppose that's made him who he is! I couldn't have cared less about the Ghullim - his time there bored me (absolutely nothing happpened) and they were poorly drawn. Yackle on the other hand appears just as I have grown to love and wonder about her, a true enigma. It's also true there are other characters I care about and wanted to learn more - Liir, Trism, Glinda and Shell certainly, with brief mentions but that is all, but as an intermediary book (I hope) we will return to their stories soon enough.
To answer a question - yes buy it, read it, marginally enjoy it and then wait for the next one.
One final thing - Unlike Son of a Witch (which I believe was written with the idea in mind) this isn't going to be a musical anytime soon.