When I first watch it I fell in love with the visual, Xu feng , Jin mi and Runyu even the villain lady is really pretty. The costume are mesmerizing and set are amazing too. Their acting are top notch I can't find fault with any of the main characters.
The OST are so beautiful I can feel the emotions everytime the ost are playing. It matches the theme of the drama vey well.

SPoilers alert
The story is really heartbreaking. I cried many times watching this drama, and I don't cry a lot when I watch drama, because I usually watch romcom or action.
They are characters that you symphatized, love and hate at some points of the drama, and .Except for the pair of queen and emperor you hate them all the time. I read some comments they hated the FL because of her stupidly naive character.
Initially, Jinmi was so naive but I don't hate her I even find her cute and endearing. However later in the story her stupidly naive traits cost other people lives , that's when I hate her.
As for the story, although there 63 episodes , it might seem long but I think it well paced, there are nice transition between the 3 realms. though I did fast foward scenes from side character which I think unimportant.
I keep coming back at youtube for clips and ost