I have one late teen and two soon-to-be-teen girls, so I know of Mr. Green. Saw the preview of the movie and it looked fun and light. I will take my two soon-to-be-teen girls when it opens at the end of July; great cover...all the other girls will think I'm a cool dad (and I am!)
It was fun and maybe not so light. I can't help but think Mr. Green is to writing (for millennials) as John Hughes was to movies in the 80's.
One last comment. "Fault in Our Stars" holds no interest for me. Two kids in love with cancer I'm out. Kids killing kids ("Hunger Games") in a dystopian future I"m all in. Sometimes there is no accounting for taste :).