Both have unforgettable characters and amazing plot. Soulful and riveting. I cried after both. After finishing Song of the Cloud, I was so emotionally affected by one character that I was heartsick for two weeks.
Palace's producer copied Bu Bu Jing Xin's premise and rushed the production to get aired first. BBJX is an once in a life time experience.: superbly written, acted, and directed with unforgettable characters.
Cruel City is very much inspired by Infernal Affairs and the Hong Kong crime noir.
Both about the underworld. While they're both thrillers, Cruel City has a noir flavor.
They're both thrilling and have a hero who loves the heroine, played by JSY in both, wholeheartedly. The hero is involved in plots with national implications in both dramas. Bridal Mask has the much better script though.
Tonally similar, thoughtful directing (same PD), poetic realism, a world that allows characters to breathe and grow.