First, I want to emphasise that I am no hater of any of these actors. I do like some more than others (Sorry Lee Min Oh, I just can't deal with you anymore ...), but to be fair, I believe that even the best actors could not save this drama.

To be honest, there was potential at first ...... and then nothing happened.
To sum up my opinion in a few points:
- Flat characters
- Relationships happening out of nowhere, because why should we spend time on building real links between characters?
- No real suspense, as viewers we often understand things way before the characters do, and really, that takes them an awful lot of time.

I love most of these actors but unfortunatly their characters are so bland that they can't do any magic here.
As for the aesthetic, it is really enjoyable and pleasing to the eyes... but that's all this drama is about: nice visuals.