They are both body-swapping dramas. Both the leads learn about each other by being in each other's shoes.
Both are mafia dramas, with male leads who have gentler personalities but have no choice but to be brutal. Female leads are naive and innocent. Both dramas have awesome production quality and unique storylines.
Similar contract marriage storyline, set around the same time period. Leads are forced to deal with a crazy nang rai trying to wreck their marriage.
The soundtracks are done by the same people (or they sound like they are). They take place around the same era, and feature a contract marriage of sorts where the leads have to go through obstacles together and learn to love each other. This drama has a very similar feel to Padiwaradda.
Both are crack dramas with super yummy male leads. They reject just about every lakorn stereotype. Both have beautiful soundtracks and gorgeous cinematography.
Both dramas have a contract marriage of sorts. The leads have AWESOME chemistry, while the stories both reject most of the lakorn stereotypes.
Love across multiple lifetimes, with leads not getting together for a long time. Couple faces many obstacles and many ghosts in order to be together.
Two former best friends fight over one man. One has a failed relationship (he died and cheated on her), and the other has many but marries the male lead. Jealousy and attempted seduction ensue.
Both have Esther as the female lead, and the same director, for that matter. The storytelling styles are very similar, with the grandma, the businessman son, and the strong family values.
Both feature leads who dislike each other at first and who drive each other crazy throughout the drama. They also both contain similar styles of over-the-top humor, mostly courtesy of the servants present.
This is the upcoming remake from Thailand that is based on the 2005 Korean version. Esther Supreeleela and Lee Da Hae are quite similar in their acting styles and look, so it's quite possible Esther will live up to the role.