Both are mini series about love. Differences: each episode of KARA has a different story, while "Love Cells"continues with each episode. Although I prefer Love Cells over KARA, both are quite good.
Episodes 9-10 feature a love story between an angel and a human which is very similar in plot and tone. He has a mission which involves helping her but he ends up falling in love with her.
first both of these are mini series and they have angels as theme. it might not be too similar but most of it refer to both romantic comedies related to angels and both have cool production set up.