The only criticisms I would offer are the myriad grammatical errors, but most of all, the poor cartography. None of the maps included basic things such as scale and it was unclear as to indications of geographical features. More maps, and clearer maps would have been useful. Being personally unfamiliar with the area, I had to obtain more information from the internet to gain a better understanding of the geography.
Should Mr Brennan write another book, I will assuredly be in the queue to buy it. Hopefully, sans the above shortcomings.