The author hates Napoleon so much it's even funny a litte. He doesn't even pretend to be impartial and objective; not even a single member of the Bonaparte family is spared (quote from the book: "Letizia Bonaparte had suckled a band of brigands and bounders on her venomous milk, pitting every child against the other, inculcating little if any sense of public or private morality, or even family responsibility." Or this one: "There was indeed something monstrous, “hard and cruel” about the man. The genes controlling human sympathy, understanding and compassion were simply missing.") The Duke of Wellington, on the other hand, can do no wrong - whatever faults he had, they were, obviously, at least according to the author, a result of a neglected childhood (quote: "Wellesley was no grand egotist like Napoleon, ... but rather, no doubt, was simply reacting to a childhood bereft of even a minimal amount of love or attention by his parents."). Even Wellington's failed marriage and infidelities was - obviously - all his wife's fault ("Kitty had proven no companion; they shared no common topic of conversation, no mutual interests.", or "The young general found that he could neither confide in nor respect this hysterical woman, and as a result, soon sought the company of other society ladies as well as a foreign command that would put much distance between him and his wife.") - see, all her own fault.
In other respects, the author also enjoys pushing his personal dislikes on the reader: a considerable portion of the book is devoted to biographies of members of the Bonaparte family and Napoleon's marshalls for no other reason, it seems, than to prove what awful people they were, because they get very little action otherwise. No such thing is done for the British or other Allies (we do not read, for example, Blucher's personal life and habits, even thogh they must have been colorful). The entire book seems to be a "Kick a Bonaparte" fest, which does not lend it credibility at all, despite it containing many relevant and interesting information.
So, sadly, a disappointed, for the sole reason of the author being a prejudiced ass.