This is my favourite drama of all times, even after watching it three times, this drama still puts me through a spectrum of emotions.
Hu Ge's acting was just amazing (as well as other casts). He himself experienced a serious accident which probably made him feel his character better. Cinematography and music in this drama is outstanding as well
What I liked most of this drama is that they trust their audiences to get what they are talking about (and to feel their emotions), without saying everything out plain. This is unlike a lot of other dramas, which treats their audience like retards. For me, this actually adds on to the beauty of the drama. That being said, it is advantageous to know the language and some Chinese culture, or have someone who is a native speaker to watch it with you. The language used in this drama is indeed poetic, and adds on to the beauty of the drama.
In addition, this drama has a reputation of being strict on detains such as the etiquette, courtesy and costumes, which matches actual history.
To me, this drama represents a warm ideal of the author, with regards to politics, loyalty and friendship and unity, which myself also has, yet not to expect in real life. Really, this will be the best Chinese drama you will ever see.