The setting of the book, the "New Frontier" in the Pacific Northwest, is very realistically imagined in terms of geography and biology. The human institutions - Harrison/Wyatt Corporation, the Colony, the military, the cult - all are very realistic, containing the biases and weaknesses that come with these organizations, and the way people with quite varied personalities function within them. The reader will recognize behavior patterns with the way these work from their real world experiences with similar institutions.
Mr. Chorman does a remarkable job of populating this world with a large number of well-developed characters. The reader gets to see the world through the thoughts and experiences of many of these characters, with well-structured shifts of perspective. This last quality reminded me of one of my favorite sci-fi books, C.J. Cherryh's "Downbelow Station."
The portrayal of the alien life forms is extraordinarily imaginative, and not at all anthropomorphized. The twists and turns of the plot keep the reader interested, and the fate of individual characters is never certain, lending credibility to the tension and interest.
The one thing I didn't find that I would have appreciated is a map of the area.