This drama is a master piece.  The STORY was a heart breaking one.  At some points,  it will make you sad,  others mad and even angry.  This drama will give you a lot of strong emotions.  Nevertheless, this drama is not for everyone.  It depends on your personality and taste. There's a lot of political issues,  family issues and people with mental disorders, this show is sensitive with the things that appear and say on it.  So be aware of that. 

The ACTING was incredible amazing.  But the one who did the best was the villain (Song Yoon-Ah)  best known in the series as Choi Yoo-Jin,  a cold and heartless woman but beautiful in the inside. She was the best character in the whole series. Lee Jung-Jin,  better know as Chairman Choi was incredible amazing too.  Ji Chang Wook did a beautiful job despite of Yoona's character,  my less favorite.  Don't get me wrong,  I did love some things about her,  and I can relate to her in some cases but I wish she was able to do more instead of crying and letting others lie to her.    

The music is OKAY and it goes with the story.   When it comes to rewatch value,  it all depends on the person,  I love this series but I won't probably watch it again because I'm not the type of person who repeats series, but maybe in ten years it would be the perfect time. It depends on the person. 

Overall: 10 stars.  It deserves it for being sucy a great drama and amazing acting.  Give it a try.