The KK team was the best part.
As with most CDramas, they broke up, and got back together, and broke up again, and got back together, and yada yada yada. I generally liked the FL, but she was a complete doormat with the boring hero, and not because she was "young." I didn't think she was "too young," I thought she was spineless and lacking in self-worth with the hero, which didn't make any sense because she came from a loving home, was brilliant and kind, and seemed to know her worth in all circumstances that didn't involve the ML. Also, it was never clear what she found attractive about him other than his looks.
Sadly, the worst part of this drama was the ML, who was straight up boring. I think he was supposed to be one of those cold / aloof male heroes-- which I usually have no problem at all with-- but he wasn't aloof, he was a snoozefest.

I did like his younger cousin, though. He was interesting, and I might give the spinoff a chance because of that character.