I liked both Raine and Karl. Raine is the typical mercenary, only taking cargo and jobs when he wants to. Karl, however, is much more than he seems. He has a lot of layers to him that slowly start to peel back during the story. Allowing Raine to catch a glimpse of who Karl really is and to know enough that he can't just let Karl leave his life now.
While I did enjoy the story immensely, I would have liked it better if the world was more developed and explained. We get the basics on what this new universe is like but I would have liked to be explained some things like why the Confed and UPA are fighting. Answers to questions that revolve around the world not so much the characters and plot. That's the thing about sci-fi, though. It's a great genre but can never live up to it's full potential unless everything about the new world that's created is explained.
Overall, I really liked this story. I'm hoping we'll get more of Karl and Raine in the future and see where their travels and lives take them. Recommended.