This is my first ever review on this website, because I just can't help how much in love I am with this drama.
I have already left essay worthy comments on this drama, but I feel it also deserves a stellar review, so here goes:

Acting 10/10: This is only the second Song Joong Ki drama I've seen. But Song Joong Ki's character is so beautifully still in this show, he never fidgets, never gets startled, never loses control of his body movements, and it's a very strong character mentally as well. It's an absolute delight to watch all the episodes again and notice minute changes in his expression to the events around him, and he really manages to exude a natural intelligence and air of authority. His character gradually learns to love, and also accept that he is worthy of receiving love, and his actions show that clearly towards the end. In the beginning he is arrogant and distant without being mean in any way, and towards the end he is loving and caring without being suffocating in every way. The perfect character development. Also his deep voice is so hypnotic at many points of time, I'm convinced that's the main reason I unexpectedly loved his character from start to finish. I have become a fan of Song Joong Ki's acting after this show.

Jeon Yeo Been, MY QUEEN, is the BEST female character ever written, ever performed, ever shown on screen. She is fiery, sassy, bright, sexy, logical, brave, quick-witted, savage, sharp tongued, and beautiful beyond compare. She matches wit with everyone around her, is funny as all hell, her voice is SO hot. She never hesitates to express what she's feeling, and loves her dad despite what happened in her past. She is protective of those around her, and willing to go to any length to achieve her goals. I am IN LOVE with Hong Cha Young and Jeon Yeo Been and this is the main reason I gave the show a 10/10.

Their relationship is EXACTLY what I want in my life. They are best friends, so honest with each other, soft around each other, support each other, communicate so damn well, they TRUST each other, believe in each other, take care of each other without it being toxic in any way, and there is NO malice, NO games, NO hidden agendas anywhere between them. They also tease each other, and never fail to bicker endlessly.
In the simplest sense, it's the PINNACLE of romance, because every single glance and touch and dialogue leaves you to BEG for more. It's pining but also SO satisfying because I cherish every smile, every action that tells everyone around them that they are a unit, a team, a couple. It's realistic because they are both logical and understanding of their circumstances, and you can clearly see the struggle they both have with their feelings, one wants to love but is afraid that the other person has to leave, the other wants to love but is afraid he will have to leave.
The ending was quite satisfactory according to me.

Other factors I want to note:
Cinematography 10/10 Just WOW. The fashion, the shots, the bars/cafes they meet in, all beautiful.
OST 10/10 I have been listening to the ost on repeat even while working, just IN LOVE with it.
Story 9/10 The zig-zag storyline was great to watch, but could've been slightly better if less background character involvement was there.
Cast 10/10 Each and every single actor did their best, and their chemistry was off the charts, insanely good.
Background characters 10/10 Most of the side-characters are interesting and fun to watch. Villains did an awesome job.
Neo-Noir vibe was on POINT. Loved the ode to black and white gangster films, I think SJK nailed that part too.

OVERALL 10/10. I have already seen this show two times.