Both season has good story line but for me the first season was the better one.
I recommended this to my friends as well and they really like it.
The visuals in the series also seems very professional and international there is no doubts that these kdrama are making the expectations bars so high for the viewers.

Also you see the importance of every relationship in your life in this drama, the relation between two friends, teacher and student, mentor and student it is defined in a very realistic way.????