Phenomenal. I can't say anything else more than this. I've only watched a handful of kdramas, but this one tops the list. I don't think I can find another one to match this one. Truly breathtaking. The storyline, characters, ost and just about everything. The chemistry between the two male leads. Wah!
If you're holding yourself back from watching this, then you're seriously missing out. Silence for those people who are yet to find this masterpiece.