The most important thing to know about Sidonia is that everyone who promised a great ending lied. Not only it's deus ex machina ending, it's also OreTata ending (yes, I learned that term from Shirobako).

The rest of the series was faulty all over, starting with a completely senseless alien threat (about as bad as one in Attack on Titan). The world creation did not pass a smell test — worlds even have floating islands from Dog Days. Only characters were okay, but it wasn't enough.

Oh well. At least we supported "anime" "industry" by watching it dubbed on Netflix. Except that it was a B-list 3D flick that perhaps did not merit supporting.

Liked: Very meh despite exciting battles and nice harem hijinks
Rewatch: God, no. Not even if they resurrect Shizuka in Season 5.