3.794 out of 5 from 17 votes
They are both reverse harem-situations.
In Shiawase Kissa Sanchoume (Happy Cafe) there are three guys who like the same girl, even though one is oblivious where as in Ouji To Majou Himegimi there are six guys who like the same girl.
In both manga's the guys are all good looking and they are both very funny manga's.
In both the main character stays oblivious to who she truly loves for a lot of the manga. In Shiawase Kissa Sanchoume the main girl is short and cute where as in Ouji To Majou Himegiri the main girl is the Princely type.
In my personal opionin, if you iike one, you'll like the other.