At some point, I'd like to finish this book, but the politics became too tedious for me. The plot seemed to move slowly. Although it introduced some interesting worldbuilding ideas, I would've liked to have seen them better explored. (But note that I haven't read to the end.)
One culture has three genders and one has five. And though there's some mention of accidentally using the wrong pronoun for people, that's about the extend of it. In practice, there are really just two genders. In one mirror world, the males are the weaker of the two, and it's really just a flip flop of our world, with women having more rights than men and so forth. I hope that the latter half of the novel would do a better job exploring this, as well how the mirror world differs in that regard, but I just couldn't hang in long enough to find out.