What I liked:
1. Complex well rounded characters with believable motivations for what they did. A bit of noble idiocy here and there but it's all very convincing and doesn't seem like merely something added to artificially create more drama. A number of characters surprised me at some point in the drama which was excellent.
2. A plot that takes you on a whole journey. The beginning is indeed quite slow but it grows and feeds the story very beautifully.
3. I haven't seen an actor as amazing as Mark Chao in a long long while in Asian dramas or western movies or ANYTHING. His facial expressions, body language, brief glances communicated complex feelings with such amazing clarity. He not only brought Mo Yuan and Ye Hua to life but also the entire drama. He was simply phenomenal.
4. An enjoyable plot with interesting and enjoyable side stories as well that are woven well into the main plot.
5. Rewatch value is 100. ONE HUNDRED, I tell you. I have been rewatching this drama since I first watched it last year. The more I watch it, the more I appreciate it and the details in the plot. The more I watch it, the more deeply I feel about all the characters.
6. Good balance of action with romance and drama.
7. I'm weird and I like suffering so I love the fact that there was some good heartbreak as part of the couple's journey.

What I didn't like:
1. CG was not that great but I got used to it after a while and it didn't affect my enjoyment of the drama as a whole much.
2. The beginning is confusing and a bit slow. (However, in hindsight after seeing the end, I enjoyed the beginning watching it the second time.)
3. First time watching a Chinese period/fantasy drama. Some things were just straight up weird for me. Can't describe it in any other way.
4. End slightly unsatisfying.
5. Slow paced at some points, some side drama was kind of unnecessary and didn't add much to the plot.

But overall, it's a yes a thousand times yes for me regarding this drama. One of the best I have ever watched.