I always have high expectations for Maria's books, and they always meet or exceed those expectations; Night Study is no exception.
There is no dull moment in this book - it's all action and adventure. The POVs alternate just like in Shadow Study, and many times we're left on a cliffhanger as it moves on to another character. It's evil but also makes the story go by extremely fast since you just need to know what happens; you tell yourself you're only going to read a few more chapters but you end up almost finishing it.
We get so much more of Valek compared to some of the earlier Study books, which is obviously a huge plus ;). He was by far my favorite POV to read from since he definitely has the most interesting (and surprising) story arc. Valek also goes through some major character development and we see him slowly evolve throughout the series. At first, I thought I would like the original Poison Study Valek better, but Night Study made me like him even more, if that's even possible.
Basically every second with Valek is like "LET ME LOVE YOU".
I would have liked to see more of Onora or the Commander and the Ixia side of things since that is where most of the unanswered questions lie; wouldn't it be fun to have on of them with their own chapters? I enjoyed reading about both our old friends and the new characters and Janco was a wonderful comedic relief, as always.
Some of the many questions left unanswered in Shadow Study are answered in Night Study, but with those answers new questions arise, which left me kind of confused at a few parts, so I am definitely looking forward to Dawn Study.
If you're a longtime fan of the Study series, you probably don't need me to tell you to pick this one up after that Shadow Study ending, but go read it. If you're new to the series or to Maria V. Snyder, start reading. There's a lot of catch up to do.