Yeah, almost all of Charles' stuff read like fic to me, but there's a spectrum and Band Sinister is for sure all the way at one end. (Admittedly my favorite of hers is the Prisoner of Zenda one which really is STRAIGHT-UP fanfic.) There's a sort of thing that Charles does in some of her books where it's like ... to me it feels like she over-corrects for safety? 'I want people to Feel Good reading this book and I don't want to include anything that might Hurt People and therefore I have carefully filed down every potentially sharp edge.' Anyway I tend to like best the ones where she lets some of the sharper edges stay and make more of a mess, but that's me.