First off thank you to the writers for not turning the woman main character into a horrible target for fanhate. I judge BL often in large part on how they handle their women characters, and while there was some fujoshi stuff peripherally, the woman mc was likable and had a personality. ??
I really liked the acting and writing. As my title says, it was not an innovative plot, but they did something much done very well. I always understood the layers of meaning the actors and lines meant to convey and they handled ambiguity well. I think also they did a good job balancing one of the main character's brattiness/manipulation with likeable qualities like humility (of a sorts, e.g., recognizing how nonsense the capitalist aristocracy in Korea is), ready forgiveness, and openness.