I liked Provenance a lot too, but for one small thing (see under 'Bad').
Good: the characters, the different human societies, the alien Geck, the writing, the way Ingray slowly learned what she was capable of and that others saw her in a much better light than she did. Also, there's a cool reference to Nilt and the purchase of a rug there which I might have missed had I not reread the Ancillary series recently. I also really liked the three genders on Hwae and how people choose theirs and their name when they become (or decide they want to be) adult. Can we have that in our society, please?
Puzzling: why were two weapons used in the murder, and by whom? There are hints pointing to at least three people but it's never made clear unless I missed something.
Bad: just one fairly small thing but it irritated the hell out of me whenever I encountered it: the title Miss. Men get Mr, nemen get Mx, but women are saddled with the insulting Miss, and that's in a society that doesn't seem to have marriage. WTH? What's wrong with Ms? That's just so wrong in a book that handles gender so well otherwise.
Anyway, if anyone has any theories on the 'puzzling', I'd like to discuss them in comments. :-) Also posted on Dreamwidth, with comments.