I liked them all, don't get me wrong, but the first one read very much like a TV show, with a limited arc and a largely episodic plot, each chapter self contained. (And while the author may have been going for a Firefly feel, for some reason all the resonances to me were ST. Go figure.) I couldn't shake that feeling, and it distracted me.

And the second one was almost too character-based. Which is odd, because my usual complaint with books is that they have too much plot, not enough character development, and on the surface you'd think this one had the right balance of both, but apparently not quite enough.

Now, book three, sure most of the individual characters don't interact much, but something about that really grabbed me and made their specific character arcs really interesting to me.