Both series explores youth and relationships between the main characters. There is romance that develops with story as each progresses. The main female protagonist from both series also has similar personalities but sometimes has a hard time expressing their thoughts. Their setting takes place at school where every day life events are relatable.
Both series are shoujo that take place in highschool. The guy plays basketball in harumatsu bokura, and in mizutama honey boy the girl is in the kendo club. Both are shoujo comedy so if you like shoujo you'll like either.
The theme of 'basketball' is exhibited in both mangas. The female protagonist finds herself surrounded by basketball players and inadvertently falls for one of them, particularly the one with black hair. Rivals are present in both mangas. Both mangas do have their differences, as in Haru Matsu Bokura she secretly meets the boys because of jealousy and popularity, whereas in Tsubasa to Hotaru, she is the manager of the basketball team.
If you have read one and enjoyed it, you may like the other.
The art style of both manga are very similar, especially the male protagonists as they seem to look alike. The female protagonists are similar in personality in which both girls fall in love first, are very dedicated, and sometimes have feelings of insecurity and shyness. While Hiren Trip deals with the student council affairs, Haru Matsu Bokura revolves more around the basketball club.