My thoughts on these three books have not changed much since I originally read and reviewed them.
In my review of The Fault in Our Stars I talked about how much I enjoyed both Hazel and Augustus as characters. I like how the book gave voice to children with illness and did it in such an intelligent yet snarky tone. I flagged so many pages of the book. It is eminently quotable, like Green always is. This plays into my major problem with this and all Green's books. I can never shut his voice out of them. I hear him every word spoken by the characters and see his hand in every sentence. I suppose this may be the downside of his Internet prevalence. I personally like authors to be not quite so present in their work. Green never manages to give his characters their own voices. I always feel like they are him.
I know the format of No Crystal Stair (my review) is problematic for many. I think it is a great strength of this novel. I love the documentary style and when I was reading it that is how the story played out in my head. I do have qualms about the very thin line between fact and fiction here, but Nelson did a magnificent job of sourcing the book and explaining her vision so I'm able to lay those qualms aside. The uniqueness of the format and the telling of a story I didn't know made this an interesting book for me. However, it wasn't one that I can count as a favorite. I will never reread it. I would probably use it if I taught middle school history or literature (the one level I don't -I teach upper elementary and high school.) I think this is mainly because while the documentary style is a strength of the novel as a whole it made it hard for me to connect with any particular character and that is what will make me love a book.
Code Name Verity has characters I can love. And do. My review for this book is vague (avoiding spoilers-which I will continue to do here) and a little overwrought. I have a difficult time discussing books I love as much as I do this one. It's all too personal. This book is full of strengths. It is constructed brilliantly from beginning to end: plot, pacing, voice, it all works. The characters are rounded and nuanced. The themes are sweeping and complex. The story itself is complex with so many shades of gray. The book is about dark times and terrible truths, but manages to convey a tone of hope at the same time. And I feel completely inadequate to discuss it. Even writing this I feel like I can't begin to the book itself justice.
So I think it's pretty obvious what my choice would be were I the judge. Hopefully Frank Cottrell Boyce will feel the same.