The story is great, I truly loved it and my emotional being couldn't really handle the end but I'm rewatching it anyways because the heartbreak is worth everything. Everything is just so pretty, the colours scheme/filming, the story, the actors, everything.
The producers really did a great job at making this, the scenery and everything was beautiful and already worth watching this. I really loved IU and the character she played, while I was watching I think I slowly fel in love with Jang Man Wol too. The fact that she left the human world at the end broke me but at the same time I also knew she finally found peace.
I loved the side-characters too, they were thought out well and really brought something to the story. It was also nice that they had backstories of their own, that way we really got to know them.
Overall I loved this and I can only recommend you watch this drama!