HOLY
excuse me
FUCKING
SHIT.
Words cannot describe this show.
You want a review? Here's my review: Watch it. Please, just watch it for the love of God. This is coming from an once Kdrama hater.  
It has everything you'll need: Best story of the millennium CHECK,  best music CHECK, best acting CHECK, that fucking plot twist CHECK, good looking characters CHECK, good cinematography CHECK
Just watch the god damn show.
Spoiler alert: It will pull you in and make you forget about life for almost two months.