The most memorable thing, to me, about The Floating Boy and the Girl Who Couldn't Fly is that it did a very good job of portraying average kids. Their thoughts and feelings were unusual for an avid reader, because most books portray magnificent and unusual people, old or young, but TFBaTGWCF's kids were perfectly tuned to their ages.
One thing I didn't like about it is that the source of the main problem here could have had been more explained, but I think that's more of a personal thing than a fault with the book, because I always love more detail. I also liked the relationship between the main character and the floating boy: again, it was like an average teen romance. The author didn't try too hard to make the Floating Boy into a stud- in fact, when you first see him, he's stuffing his face full of food, and that new perspective is realistic and refreshing.
I'd say this is a good read also because the pacing is done well. Halfway into the book you still don't know why all the odd things are happening, but I didn't care because I was enjoying the story, so even if you're not sure whether or not this is for you, it's worth a pick-up because it reads like butter.