Watched it with a group not so long ago. Started very well but it felt repetitive by the end of the first series; this is a very strictly episodic show, nothing is learnt or changes from episode to episode. And it's often quite grim - not the scary kind of horror, but remorseless fate crushing humans who stray from the path. It became a running joke for us that characters we saw early on would die by the end of the episode.

Rational for the subject matter perhaps, but these are still fundamentally folktales; there is no logic to what constraints any given mushi will have, and so you can't use reason to predict what will happen in a given episode (storytelling logic, and the idea that the ending is at absolute best going to be bittersweet, yield much more reliable predictions).