I love books that takes a very clear premise, and build a story around them. For example, the premise here what a civilization whose members were ambisexual would look like.
This premise provides an intriguing frame of reference for an analysis of gender relations, and how they have come to shape our civilization; in the same way that dystopian novels often critique contemporary society. The most interesting part for me was the self-revelation the Envoy has about his own gender prejudices and their endangering his mission to establish diplomatic relations with the planet of Winter.
I found the glacial trek that occurs reminiscent of something that happened in Anathem, and I wonder if this was the inspiration.