It's just... mediocre. Copy pasted storyline and cliches, with different actors and actresses. I rarely watch kdrama, and I still feel bored to death.
Let's start from the storyline, non-human ML who helps FL in distress. This one is a devil, the previous one was a goblin.
The acting is so-so. The actor is an eye candy, though. But it's cheap even for cheap entertainment.
The music is the best thing in this kdrama, I guess? But this isn't a musical drama. They should have put at least as much as attention they give to ost to the story.
Rewatch value? If I can give negative value, I would.