My one complaint about the first book was that I didn't feel like I got to know any of the characters well enough. That was absolutely resolved in this second book. Even though we spend time in the heads of several different characters, I still felt like I got to know them--especially Dym and Raz and Ivan--much better than I felt like I knew Kin and Kyo.
And what I loved about this one also is that it feels so much more hopeful. Sure, some bad, scary, terrible things happened, but the atmosphere (perhaps because of Raz's innate optimism) never became dark. And things worked out in the end in such a way as to leave me hopeful and trusting that the final end to each sub-story and to the series as a whole will be just as beautiful.
The world continued to be fascinating, and even though I'm only just done with the second book, I can't wait to go back and re-read the series. There are so many moments (looking at the stained-glass windows, for example) where there were elements I know I'll love looking back and remembering but which I simply haven't discovered yet at this point in the series.
Without question my favorite m/m fantasy series I've yet discovered!