I don't think Luna really changed much. She was awesome to begin with.

He went from being scared to being couragous!

Neville for sure

Definitely.

Luna didn't really change. She was the same in the fifth book as she was in the seventh.

Luna stayed as odd and as sweet as she was in the fifth book. Neville however... he changed a lot. I don'T say in a bad way, because it's obviously not bad, but still something about the DH Neville just doesn't come through for me.

Luna always had confidence and self-assurance. She always followed her own path, from the moment she was introduced to the last book.
Neville, on the other hand, used to be scared of his own shadow. But he grew and changed through the books, gradually finding his own way and gaining confidence in himself. And when he was truly tested he stepped up to the plate and proved that the Sorting Hat did not put him in the wrong House. Besides the Trio he was the bravest Gryffindor of them all.

Luna was introduced in the fifth book, so we don't actually know what she was like in the beginning. Since the fifth book, she's always been eccentric, and imaginative and she was still like that right before the series ended. Neville, however, is a completely different character now!

He used to be awkward and scared in the beginning. As the years passed, his courage built up, his loyalty started showing and he became a lovable character.

I love both these characters, but I suppose I'll choose Neville over Luna BECAUSE I've seen Neville progress as a character from the first book to the last.

luna doesn't change at all. she stays her same quirky self.

Neville, changed from frightened to brave!