Cast:
The cast for this drama is great and I was expecting quite a bit, but it just didn't work. Luo Lunxi is a good actor and that is undeniable, and in this drama he performs well and embodies his character perfectly. Cheng Xiao, on the other hand, is considerably newer to the acting world, and although her performance in LTL is much better than FIYS, she still lacks in many ways. I find that she doesn't fit the character she plays, and the FL and ML put together just don't have that chemistry that I look for.
The side characters are possibly my favorite part of the drama, and each one of them portrays their role so extremely well. Huo Jian and Xie Ming Hao are portrayed very well by their actors, and give a very convincing performance to the point where you hate them when you see them. Everyone does well in their roles, and I think that overall casting was done really well for this drama.
Plot:
When I watched the trailer and read the preview, they were extremely intriguing, and when you watch the first few episodes, that's exactly what you get. However, after around 15 episodes, the story starts to drag. This may be due to the fact that most c-dramas are stretched to 30+ episodes, leading them to needing an extra segment. Both villains are extremely important to the plot, but that period between the two villains is what I think is dragged out. The romance between the two leads is similar to that of a fairytale, with no real issues, and although it is a good watch, they put too much time into it IMO.
OST:
There's really no debate on this, the OSTs for LTL are insanely good, and they fit the story very well. I've had the album on repeat for awhile now and I still want to keep listening to them. I think that the OSTs were made extremely well, and that they are one of the parts that I look forward most to.

Overall, this story is a good watch, but there is a certain number of episodes that aren't exactly necessary.