It was a good show to begin with, but I think s2 improved a lot by every character more or less knowing what's up and having their loyalties clear, especially both senior Byrds. I also think they've made a good job of finding obstacles that seem organic from within the story and at least remotely believable, something a lot of other shows struggle with.
What I like most about the show is the constant, but fluid, shifting between dark and witty humour, thriller suspense, but also a sombering seriousness that kind of goes beyond the plot, like Wyatt's essay.