Jinsei

Both are about unusual clubs centered around conversations in their everyday life. Each only have one boy surrounded by girls with a wide variety of peculiar personalities. If you enjoy slice-of-life, laid-back comedy with a hint of romance, and occasional fan-service, then you'll probably enjoy these two titles. Jinsei happened to featured a cameo of a character from GJ-bu (Amatsuka, Mao) in the first episode as a small figurine. Just like GJ-bu making a subtle tribute to Evangelion, Jinsei looks like it will also feature more cameos, tributes, and Easter eggs to other anime and pop-culture references.  

Both are school comedies featuring primarily perverted humor. The main characters consist of a group of girls and one guy. However, in Mitsudomoe there is a large age gap between the girls and the guy (he's their teacher), whereas in Jinsei the characters are all the same age. Both shows also involve a superhero or group of superheroes who are important to some of the characters. 

Cute girls dealing with the problems of love and life. 

Both are about a guy joining a club and they participate in that specific clubs activity(s). Both are filled with slice of life humorous anime and take place within a school. 

Both are anime about a group of girls (in jinsei there is one guy though) who have conversations about random subjects. 

Both series are romantic comedies, to an extent, that focus purely on couples of one person and one other person: these are not harem series. Revolving around random slice-of-life activities, both series do a great job of combining them with the romantic comedy elements; never making one overpower the other.  

Both anime gives comments in a very weird way. While watching Jinsei it reminded me of SYD. Both Tsuda Takatoshi (SYD) and Akamatsu Yuuki (Jinsei) has difficulties handling their normal life because of the girls in their school. 

Both are comedies setted at school where group of people (club/student council) full of people each weird in it´s own way helps other students. Both have perverted moments but Medaka Box has more action.