Like many others, I picked this up because of the Oppenheimer movie, which I quite liked. Obviously, the book is different from the movie, but I found both worth the time I put into them. 
This is a really well-done biography; I totally understand why this received the Pulitzer. There is so much material to pull from when it comes to Oppenheimer’s life, as there are reams of government papers on him. The authors also conducted extensive interviews with those who knew him. 
The picture of Oppenheimer that emerges is that of a complicated man. While he himself is interesting, I also enjoyed learning more about US history through the lens of his life—especially in regards to US atomic policy. Overall, this was an excellent read if you are in the mood for something dense and thought-provoking.