Basically, Boku no Futatsu no Tsubasa is what I hoped No Bra would be: a funny gender-bender manga with decent story. BnFnT has the same kind of gender-bender explorations No Bra has, but drops the shounen-humor for a combination of regular and slapstick comedy. Overall, I found that BnFnT took a better, slightly more serious approach, while keeping it plenty funny. Give it a shot if you enjoyed this one!
Fifteen-year-old Tsukune Aono is average in every way; he has no hobbies, less-than-stellar grades and he's even flunked his high school entrance exam. His parents have managed to enroll him in a school, but it's no ordinary school! Tsukune will be attending the Youkai Academy, a place where monsters learn how to co-exist with humans! As the werewolves, vampires, witches and other monsters are required to retain their human forms, Tsukune - the lone human - is able to avoid their bloodthirsty gazes. However, he quickly attracts the attention of a number of devilish beauties including the vampire Moka, a busty succubus and even a young witch! It seems Tsukune's average life isn't so average anymore!
Shuichi Nitori is an elementary school boy with a secret: he wishes he were a girl and likes wearing their clothes. With the right outfit and his cute, effeminate looks, he is often able to convince people that he is someone else - or even something else. Unfortunately, although his best friend and object of affection, Takatsuki, accepts him as he is, she does not return Shuichi’s feelings. Moreover, school is an unforgiving place and Shuichi walks a fine line between liberating his true self and being labeled a freak by all his peers...
If it's mainly the gender-bending/transsexuality aspect of No Bra that you found interesting I recommend that you read Hourou Musuko, which deals with these issues in ways that are more nuanced and well thought out. Be advised though that Hourou Musuko is devoid of fanservice and ecchi.