The writing is ok, the story is good, but I don't remember the last time I saw the main character being such an egomaniac and an asshole. As I was reading the book, I did not root for John at all. Any situation that could have been just a normal conversation, he converts into an argument from the very first sentence he speaks. Insults everyone around him. God forbid anyone tells him "his shoes are untied", he'll yell at you and promise to destroy you, your family and all your friends...
I don't get the idea behind writing a character like that. As a reader, you're supposed to like characters, not despise them.