Just finished as well! I'll attempt to keep any major spoilers out until everyone else has read.
This book reads a lot like an episode of star trek, which made for an overall enjoyable read. I liked several of the new characters, and the flashbacks were some of my favorite parts. The overall story shifts between two main 'plots', although one at times feels a bit superfluous.
What I think people will most like about the book is where it leaves off the series. If you've had any complaints about the current story-lines, there's a good chance you'll be pleased with how the story comes to a conclusion.
Its hard to critique the book without talking about the fall series entirely. I think while overall the story was quite good, there may have been a bit of an over-complication of events. By the end of Peaceable Kingdoms
there are two fairly huge conspiracies. I feel as though expanding upon one of them would have been preferable to using both. I'll probably elaborate on that further when more have read.
Then, I have something of the same complaint as I had about Typhon Pact, except moreso. Each of these books is supposed to be read as a stand alone. Except there's clearly a progression of events and information for the reader to receive. There's a big difference between 'each story is stand alone', and 'each story has a self contained story within it'. I would rather see crossover books numbered so that less time could be spent explaining what is going on. I completely get that readers need to be 'reminded' of things that happened in prior books... but there is a ton of explaining done in Peaceable Kingdoms
. At times that got very tedious.
Overall though, this was the first series of trek lit I got to read as it was released, and I really enjoyed the experience. I can't wait until the next grouping of novels comes out.