Wow. What a journey . . . what a long, long journey. Having read a digital copy of this book, I had no idea it was over 800 pages long. But I certainly felt it. 
 The ending was perfect, not a sugar-sweet, saccharine-coated fairy-tale ending, but one where the characters were recovering from a long-fought battle, dealing with new scars yet planning the new future they worked so hard to forge. Loose ends were wrapped up, enough so that you know there isn't going to be a hail-mary continuation of the series later on (and you don't need one, either), but some things were left just uncertain enough to sit on and imagine the characters overcoming in the near future. I'm glad I saw it through to the end. 
 However, the journey to get there . . . though I think the entire novel took place in a few days or a week or two (at least, once they got to Luna), it felt like months and months and years. While it was never slow enough for me to be even the slightest bit tempted to drop it, I did feel impatient. Though I don't know that I would cut any of the subplots, the book did feel just monstrously long at times. 
 And really, the length is my only complaint. Everything else was fantastic and lived up to the novels before it. The conclusion was definitely worth the struggle to get there, and in the end, that's all I really want from a novel.