I also just read this book at Mare's recommendation and will echo her thoughts! It was a great read! I wasn't sure if it was considered YA or not because, although the main characters are teenagers, it wasn't written in a cheesy, cliched YA cancer kid story way. In fact, it even mocks that genre in the book LOL.
I loved how honest and realistic and CURRENT it felt. You can tell it's a new book because it contains a lot of current pop culture references and modern slang (my favorites were the America's Next Top Model marathons and use of the word "douche" LOL). I was surprised to get to the About the Author page at the end and be reminded that the author was a guy because he wrote the narrator, a 16-year-old girl, SO WELL.
What I didn't love so much was the way Hazel and Augustus actually talked to each other because that didn't feel so realistic - they had a case of the Dawson's Creek/OC syndrome, in which teenagers are far wittier and more pretentious than kids in real life. But their dialogue was clever and often very funny, so I can forgive them that one flaw.
It WAS very funny. I may have shed a few tears, but I laughed a lot more than I cried. My favorite books are the ones that get me to do both, so two thumbs up to this one!