Where Orbitsville's strength was its focus on individuals, Shaw here takes a good idea too far. Departure is basically a mystery story in an SF framework. It's good, and Shaw shows his usual deft touch with human character. Dallen is a complex, conflicted man, but also a bit slow. His struggles with how to deal with the emotional difficulties of his situation are tone perfect. Unfortunately, they're a bit overwhelmed by his simultaneous obsession with a simple plan - vengeance.
There's also an interesting large scale science fiction story here, but Shaw provides it in a clumsy chunk that screams "cash-in sequel". I wish he'd taken more time to lay the groundwork instead. There are good traces, but the resolution of the story is just too unwieldy for that thin framework to hold.
Probably best read for the mystery element, and the portrait of a stolid, physical man in distress. A decent story, but fans of Orbitsville may be disappointed.