Both Chinese dramas are about a person who changes sex on kissing. In rules of love, Luo Tian who has identified himself as a boy becomes a girl on kissing the ML while in Only Kiss without love, female Tong Tong becomes a man on kissing a mammal.
The base story is similar. The female protagonist enters an all boys high school, under the hidden identity of a boy. Also, she lives in a dorm and shares room with boys. She must not let anyone find her secret before she accomplishes her goal.
The female lead enters an all boy band AN Jell, disguised as a boy, to help her twin brother.
She'd have to act to be him and not let anyone find this until her brother returns. Her hardships to protect her identity increases when she has to live with the band members.
Both dramas have comedy and a female lead that must disguise as a male.
However, Bromance is set more in a business-like setting and does not contain fantasy (it just contains some fortune telling).
Both dramas include:
-Main female lead disguises as a male
-School (college) environment
-Female lead and male lead are roommates
-Female lead falls in love first
-Both the female lead and male lead are athletic
Both dramas are filled with countless troupes and cliches, both share the crossdressing and cohabitation tags. Although, My Unicorn Girl has a higher budget, if you are a sucker for troupes and dramas that kinda parodying them, then you can try the other out.