Marginal Prince: Gekkeiju no Ouji-tachi

All-boy school. Hints of BL relationship. Similar set-ups. Similar situations. In a sense, the 2 series are basically "siblings". similarity: 4* 

Both have very beautiful male characters in a school-setting. Meine Liebe is placed in the past and its tone is a lot more serious and darker, but but both have a conspiracy going on in their plotline. So, if you've watched Marginal Prince, try watching Meine Liebe (and its sequel Meine Liebe Wieder) too. 

A bishounen cast of talented "Princes" surrounding one (female in UtaPri and male in Marginal Prince) character that is not all that special in comparison. Main characters in both series attend an elite school where, at first, they feel like they don't quite belong. Every character in both series has different personalities and backstories that are presented in one episode each. Also, they all tend to burst out singing in one point or another (while the singing is good in UtaPri, it's really just amusing in Marginal Prince because it's so bad). If you enjoyed Marginal Prince, I'm absolutely positive you'll enjoy UtaPri, but I can't make any guarantees if it's the other way around. read more 

mysterious "prince" theme; elite school; exalted feeling in the beginning you often think "what the heck is going on?" both seem to be meaningless, though Utena isn't, and Utena is much better :P 

Same Characters Design and Plot. 

Despite the fact that Angel's Feather deals with supernatural while Marginal Prince doesn't, they both take place at an academy, explore boys' relations and have similar character types. 

Both series follow a clique of students and their silly adventures at an all boys school. Family troubles balance the mood and both have their own unique entertaining quirk: compulsory crossdressing in Princess Princess, episodic nonsequitur singing in Marginal Prince. 

Both an all boy school 

One boy (with OHSHC it's a girl) coming into the lifes of other, quite important boys. I think Haruhi from Ouran High School Host Club and Yuuta from Marginal Prince are the same- they try to help other people out, talk to them, get to know their past (and sometimes future), warms one another's heart, help them sort their problems out. It may not be the same setting, but OHSHC was the first other tv serie that sprang into my mind when I watched Ouran High School Host Club. You can always watch a trailer on youtube if you're not sure whether you'll like the serie. read more 

Both are about a group of "special" students, variety of characters and animation are quite alike too. Both series also have very similar feeling to them.