I LOVED this drama, my first Taiwanese drama and I don't think I'd ever find another Taiwanese (Kdrama or Cdrama) drama as good as this one. It's a mixture of: W - Two Worlds and Extraordinary You.
What I loved about this drama is that the "dream" world was in fact real, at least to the ML and FL. Unlike many other shows where the other reality is only real to just the ML or FL, here it was real to them both, which is the most important aspect of the story.

There are essentially two romance stories in this drama between the main characters:
1) Book (dream) World: The story of how the Xiao'en and Aoran (book name of He Tian Xing) fall in love.
2) Reality (awake) World: The (much shorter) story of Xiao'en and He Tian Xing falling in love

I loved both love stories, but they were both very different. You'll understand just how different the book world and real world stories are when they collide and litterally break apart at episode 15. I preferred the real world Tian Xing over his book world counterpart. He was better in litterally every aspect and I wish we got to see more of him. Tian Xing himself said that he didn't like the person he was in the book world. I wish we had more episodes in the real world rather than the book world. There was also a lot more action and subplots in the real world story that I wanted the FL and ML to experience more of. Other than that, the story was PERFECT. I did have to skip some parts of the drama because the FL really made me cringe sometimes.

Another thing I have to mention is the CHEMISTRY between the FL and ML. It was SOOO good. I really want to see another drama with Vivian and Marcus as the main leads. I mean even before the two charecters met, you could see the chemistry. And when they were together, even when the characters hated each other, the chemistry was EVERYTHING.