Personally, I think the Yangchen novels are better. I like how Yee had a different approach to those books, making them spy thrillers instead of the adventure stories we've come to expect from Avatar. For me, the real problem with the Kyoshi novels is that they feel inconsistent. The Rise of Kyoshi feels like a season of television put into one book, and against the odds, it works really well. There's a reason it usually wins best Chronicles of the Avatar book. But, I think it falls apart with The Shadow of Kyoshi. The sequel feels like it focuses too much on the lore (and I do love lore, don't get me wrong) and not enough on the original characters from the first. I was really upset when The Flying Opera Company only appeared in the 3rd act, since they were one of my favorite parts of the first book. I also think the ending of The Legacy of Yangchen got to me, considering how emotional it was.