Very mixed feelings.
OTOH, I liked the thought-provoking premise, with early episodes engaging me in the passengers' and their families' and friends' complicated emotional struggles with the real-world consequences of their disappearing and returning. OTOH, I find the later tight focus on the "lifeboat" hypothesis and Ben's determination to save Cal at almost any cost less appealing. And the science vs. faith conflict seems overly simplified
That said, I can see that one purpose of the later plotting and writing might have been to make Ben less heroic and more obsessively hysterical.
I will watch Season 4 to see where this goes.