First of all, this drama looks amazing. The sets, the costumes and the acting are awesome. There is no evil psycho-jealous-type character in 70 episodes and that is really rare for a palace-drama which has quite a focus on romance. This drama will have a special place in my heart because it jump-started my interest in Chinese dramas.

Story
It starts phenomenal as the storyline gets unravelled and you get sucked into the story. The characters are very interesting, especially the 6th prince Ning Yi. The scheming and the intrigues in the palace are very entertaining because of Ning Yi who adjusts to the situation at hand and controls how people see him and the emperor who is not an idiot (which is very rare in my opinion lol).
The ending was not bad, but I guess after all the episodes I just started to expect way too much.

Acting/Cast
The cast did an amazing job, especially Chen Kun as Ning Yi (6th prince) and Ni Da Hong as Ning Shi Zhen (emperor). I loved their interactions with each other the most. The rest of the cast also did an amazing job, but these 2 just stood out for me.

Music
I personally don’t pay much attention to music/OST so I can’t really judge but I certainly can’t complain about it.

Rewatch Value
I don’t really rewatch dramas. But looking at 70 episodes à 45 min, the drama being an eye candy and the amazing acting, I guess it’s worth a rewatch because you will probably miss a few things and you get to enjoy a fantastic show.

Overall
This drama has sweet and mature romance, cross-dressing, hidden identity, revenge plot, power struggle and palace/political intrigue. For me its basically a palace drama done right without the annoying psycho-jealous-evil-mastermind-character and the female-lead character being thrown into the cold-palace/hard-labour-department because of a misunderstanding.
I would suggest to at least watch the first few episodes to get a feeling for the drama and of course to be amazed by the costumes and the acting.