I wasn't too interested in this book, the religion aspects made me wary. But it fulfills my needs for a good sci-fi book, woman author, character development trumping science, first contact, alien environment. So I read it anyway. The religions are interesting and handled from an analytical pov, even from within the characters own minds. 
 Thinking back I'm not sure the book managed to pass the Bechdel test, and there were several moments when I got side-railed by an inauthentic female voice. I mean, yes, the main story involved priests, but there were two significant female characters that just seemed to fall into lover, mother ideals. (view spoiler)[The big crushing secret that broke Emilio is a stay at an alien brothel where he was repeatedly raped. I found it a bit gimmicky. There's a lot of talk about choice, and sin. In contrast to the handling of the female character's stint as an actual prostitute. Which is not mentioned except for how she deals with it stoically and privately. It also makes her frigid. You know, until she falls in love and gets pregnant. (hide spoiler)] 
 The shine wore off the book slightly when in the author notes Russell appears to sympathize with Columbus and denounce "revisionist history" and sort of make a, "those men were doing the best they could" hand wave. I'm fairly certain that she wasn't talking about genocide, but the Jesuit priests. Unclear. 
 Throughout the book the first contact group makes a series of horrifyingly obvious mistakes. They had years to train, and make choices that any recreational reader of sci-fi would avoid. There are a lot of cultural and biological assumptions made. Which I guess was intentional to play into the New World/Missionary parallel. 
 Overall, I enjoyed this book. I read it pretty much straight through, good pacing, interesting story. Enjoying it less now that I wrote this review.