It was nice because it was a short history, and it was informative, but sometimes got too much into the theoretical (why Leonardo did something) and drew on psychological/sexual impetus for his paintings, especially when it came to the Mona Lisa. Also it spent too much time addressing popular belief that Leonardo was homosexual, which the author believes is possible, without actually giving evidence or reasons why he was (the author discounts the one event that most historians use to justify the homosexuality).
The book was informative and demonstrated Leonardo as first a scientist and an artist second. The tragedy and failure of Leonardo's life (in my opinion) was he was so caught up in learning that he never took time to share the knowledge. After his death it was lost. Many of his discoveries were made hundreds of years before they would be discovered by others. Unfortunately no one knew that since most of his scientific writing was not found until after the fact. He could have advanced medicine by a hundred years if he had taken the time to share his knowledge.