Jason and Marceline is a coming of age story about waking sexuality. The ending was 'okay', but not spectacular. In essence, it is exactly what usually happens in 9th grade with 9th graders. However, as a reader, it is unsatisfying that Marceline would get back together with Jason after the way he treated her. He still wants the things that he wants and the reader is left wondering if she will eventually give in.
The character most find interesting in this is Marceline. She has it all, but risks losing it because she refuses to give in to peer pressure, and pressure from Jason to do things that she isn't ready to do. This makes her courageous as she stands up for what she believes in, even in the face of great adverisity.