Having just barely finished the book, I was impressed by how much attention was given to both the earlier and latter parts of his life. Much of the details available (for free) online tend to gloss over the life of the young Tesla and only rarely go in to detail about his last years, and those are usually to attempt to denigrate the great man.
As others have mentioned there is some glorification at the expense of others, but this seems to be representative of Tesla's sometimes vainglorious, often pompous self-opinion as evidenced by the many letters between himself and his friends, not to mention those that opposed and/or profited from his many patents. Towards the end of the book you can almost feel the authors frustration at how Tesla often got in the way of selling his own work by force of his personality, which seemingly helped create his status as a (even if much lauded) pariah.
Tesla's personal correspondence is extensively documented in this book, sometimes ad nauseum, but it gives a great insight in to the mind of the man himself, instead of relying on secondary or tertiary sources.
My only real disappointment, is the lack of technicality. For a biography based around someone who's inventions have in many ways powered the modern world, the workings of those machines are barely touched or at best the details are fleeting and textbook. I should imagine many readers who bought this book, didn't do so because they are followers of the cult of personality so prevalent in many modern biographies, but because of an interest in all that Tesla both created and theorised.
All in all a good book, and a very comprehensive history of the man and his mind, if not the minutiae of his machines and ideas.