There is the age gap between the leads. KWUWA is a little heavier, with a bit less romance. Not as fluffy as Kinkyori Renai.

Both leads own the company where the female leads are employed. Boss vs Employee romance. And the romance (i.e. the leads caring for each other) is off the charts.

Both male leads are quirky with similar mannerisms. And they both love the female leads so very much. Also, there's the rich guy, poor girl thing going on.