There are many similarities in both series. The Last Empress is more overtop and Money Flower is more subdued.

The plot centers around a rich boy who likes a poor girl and his three other friends. The friends in Rooftop Prince remind me a lot of the F4 in boys over flowers.

Both focus on a lot of office dynamics and changing the company to be a better business. Both are focused on becoming better people.

Lawless Attorney and City Hunter are both exciting tales of revenge. There is a lot of action in both series.

Both Refresh Man and What's Wrong With Secretary Kim have few similarities, such as leads knowing each other when they were younger, the CEO/ employee relationship, the impossible to please boss, rich man, poor woman trope. The reason I do recommend Refresh Man if you liked What's Wrong with Secretary Kim is they both are written well despite their overuse of certain tropes and cliches.