I approached this book from the perspective of a long-term WoW player, rather than a student of sociology (which, with a background in geology and photography, I admit I know little about).
At first I enjoyed this book. I'm about halfway through now, but sadly have very little motivation to continue. There are several glaring errors which WoW enthusiasts will notice. On page 108 the author asserts that only mages are capable of summoning a character, when in fact only the warlock class is able to do so. Bainbridge also states, earlier in the book, in one of his many explanations of WoW mythology and lore, that the Old Gods were responsible for forming Azeroth and appointing the Dragon Aspects, which is utterly incorrect. There is also some confusion with Naaru technology (the Exodar isn't a spaceship as asserted by the book.. it's a dimensional fortress, which travels through the Twisting Nether rather than space), Tauren history (being formerly nomadic, they have only recently settled and do not enjoy the untouched cultural continuity described in the book), and the transmutation of primals (though I believe that this was a mistype rather than a lack of understanding of the process).
This may all seem rather pedantic, especially in a book which otherwise seems good, and whose positive approach to gaming I applaud, but I simply cannot take an academic book seriously when it contains mistakes which would be spotted a mile off by anyone with a passing interest in Warcraft lore. (Added to the occasional dodgy bit of proof-reading, which allowed the incorrect variant of 'their/there/they're' to slip by unnoticed.)
On the other hand, from what I have read, the WoW-errors do not have any noticeable impact on the sociological arguments made by the author, so if you approach this from the sociology student angle, and don't play WoW yourself, I wouldn't worry too much.