Broken Base: The Eclipse Phase elements have been contentious, especially on Spacebattles. The author himself said he was hesitant to even use EP concepts precisely because of how "neurotic" people were about the setting. Some readers either expressed doubt or even swore off the story because of weirdness like uplifts and mind-uploading, while others were upset because there wasn't enough of the society-altering technology of Eclipse Phase included.
Ensemble Dark Horse: Garm. The author was actually worried about the reception that he'd get from the fandom because of how bizarre the character was, but he's proven to be one of the most popular characters in the story, period.