I've seen my share of dramas. I think I've seen most of the dramas that are considered "the best". As for now, Mr Queen dethronised all of them and is my number one:) Things I like about this drama:

1) Great leads: It's the FIRST drama where I wasn't annoyed at any point by FL or ML actions. I just loved them throughout all the drama. the chemistry was spectacular. There were no clisches in their relationship which was refreshing. I don't have to add that the actors who played the MC are now my favourite k-actors:P
2) Lovable supporting characters: sometimes you don't care about supporting characters but here you do and you love them as much as the main couple:)
3) Entertaining plot: there were NO dull moments, all episodes were fun and entertaining and brought something new to the plot. I have to say that I'm not a big fan of historical dramas, they're usually to serious for me that's why I loved this more contemporary approach.
4) Music: music was just perfect and so on point!

The only thing I didn't like was the ending. The drama made me believe that love is just love no matter the gender. Ending distroyed this belief a little bit by playing it safe. However, it's still my top drama and I recomend it to everybody - you won't regret watching it.