This is the first science fiction book I've read. I really really liked it. I've read a lot of young adult books and this was totally fresh. No vampires, no witches, no sex (well there was the mating season on the ship, but the main character's never got involved), no gossiping or superficial characters, no love triangles (though I thought it might be heading that way), etc. It was just very "mature" in a good way. I enjoyed the writing and the unique storyline very much.