Prey is cleverly written; we find out what Krin is by how she acts and interacts. The characters make sense from the beginning and our understanding of them grows through the story. I love the subtlety and parallel to a classical story (a very obscure parallel until the very end, so it doesn't ruin the ending) but even if I didn't pick up on it, I would think it is a well crafted story.
I can't resist sharing my favorite lines, "Her ears went back to the angle of disgust. Traitors: may they all go to Tlar with fur in disarry!"
There is one somewhat jarring note... WARNING: POSSIBLE SPOILER IN THE REST OF THIS REVIW............... I can believe Creslot learned a few words in Krin's language but not that they would include the ones he used later. I don't think a universal translator explains that. It doesn't make sense that it would give those words without giving others would have been as useful or more useful later and much easier to figure out from the available contexts.