I must say that I enjoyed more Marissa. She wasn't afraid to acknowledge her feeling like Adam.
I understand and honor Adam's choice to take place of his friend, but he exaggerated! To me it seemed that he wanted to exchange his life for those of his friend and, in my opinion, that's a very wrong thing.
But in the book that was well explained and I didn't let this my opnion infuence me or make the book less enjoyable! :D