I enjoyed this show, and agree with you about the ending -- it is incredibly tough to take a time traveling plot with lots of moving parts and wrap it up as well as this one did.
I watched it initially when Cali posted that news about his kid's involvement. First season was enjoyable, second one was kind of meh. When they did the thing last year, posting 4 episodes per night over a weekend, I wasn't sure whether to continue watching, but the season 3 plot moved along briskly and was enjoyable.
This final season was terrific, and the primary actors are really top notch. The subject matter might not be for everyone, but as TV shows go [especially ones focused upon implausible sci fi oriented subject matter] -- it doesn't get much better than how satisfying that ending ended up being. ESPECIALLY because it ended kind of on an opposite note than a series like Lost, which didn't even attempt to wrap up the dozens of unexplained loose ends -- this finale accomplished that, and was still compelling. Hats off to Cali's kid.