Butler, imo, is somewhat overlooked as one of the premiere social science fiction voices of the 80s/90s. Though her work is becoming more recognized than it used to be. I think she tended to get stuck into a niche of “black female SF writer” that was hard to break out of. But yes, the Xenogenesis work is very strong–it certainly should draw comparisons to LeGuin’s work–and much of her other work is equally solid.