The story captures both Halkeginia and SAO very well. It's unique in that it concentrates on the political and social consequences of the World Tree being transported to a 'real' fantasy world, both from the perspective of the major players of Halkeginia and the players of Alfheim. At the same time, it avoids the obvious pitfalls, like Louise receiving a Familiar Sue, and Stages of Canon.
The author tries to tell everyone's story, and has so far succeeded splendidly. All of the characters are engaging, from the shrewd Alicia Rue and Argo, to the loud Guiche, to the insane Cromwell. The world feels truly alive. As per SAO, the tone of the narrative swings between comedy, tragedy and action, frequently in the space of a single installment, or even a single scene.
While there are infrequent grammar and spelling mistakes, they invariably come from the author or proofreader being too trusting in the auto correct. Even so, they do not distract from the flow of the story too much (and that is coming from a Grammar Nazi
Currently clocking at 12 chapters and a load of supplementary material, it is out there together with The Hill of Swords as one of the best ZnT crossover fics I have read.