The thing that I liked most about this book was the depth of its world. Many authors will create a "new" world by slapping together various elements of cultures that either already exist, or that other authors have created. Le Guin's book, however, achieved much more than could have been done with that method. She created her own new world which was simultaneously understandable and completely different from anything this earth has ever seen. This is a rare feat. 
 Another of my favorite things about the book was how in-depth (there's that word again) Le Guin was in her descriptions of an "ambisexual" society. While I have read books in the past that have had similar people, I have not found one with an entire society of them, and had not considered the ramifications. 
 This book loses points because it didn't seem to have a really strong conclusion or climax. It was mainly an account of Ai's journey on Gethen/Winter and his friendship with Estraven, which was very interesting, but lacked a strong and unifying conclusion. Also, it lost some because (view spoiler)[Estraven dying at the end (hide spoiler)] was hella depressing, and because (view spoiler)[Estraven and Ai never had sex (hide spoiler)] (admit it, you were waiting for that scene for the entire half of the book). But I was very, very close to giving this book 5/5 stars.