This book broke my heart.
First off, The Mr. Coreys, you aged all our protagonists 30 years. THIRTY YEARS. You have 2 more books to write in this series. Meaning, you expect to actually kill them off in the last book? I don't think I'm ready to think about that yet.
Second, you did the thing I was bitching about 3 books ago. You split up our protagonists - again! - so they had to fend for themselves. (And fight a lot while they were at it, which broke my heart some more.) Based on the ending, I believe I know where you're going with this plot twist, but I sure don't have to like it.
Third, you tried so hard to write a believable villain (not the main guy - he's not a villain - the guy who ran Medina Station). Unfortunately I found him a little bit too see-through. You pushed the "loving his family" part too hard so he became a caricature rather than someone we could empathize with.
If it weren't for the fact that you bring out a book a year, I wouldn't have the courage to stick with this story. I adore this writing more than any other sci-fi right now, and I'm sure I'll be heartbroken in a different way when it's all over (what, no more of these novels??). But at least I won't have to fear the next one anymore.