Manga Thoroughly mediocre, but not as offensive as it could be
No Bra doesn't have a lot going for it. The art is not very good; the events are mostly the type you'd find in any seinen school romance, and the characters are very cookie-cutter and often unlikeable. Even Yuuki is just a typical Yamato Nadeshiko type, apart from her physical sex. Basically, one of the main girls being physically male is this manga's only twist on the usual seinen romance/comedy setup, and by the end of the first volume or so it's starting to wear thin already.
The one thing No Bra does do well — or at least unusually well for this sort of manga, which is not saying very much, but which I still found pleasantly surprising — is its handling of a transgender character. Though the main character is a jerk about it and the Bridget-dropping is often played for laughs, the series makes no excuses (at least as far as I read) for Yuuki's desire to present as female. It's not because she's in love with the main character and thinks he won't accept her as a male, it's not because there's some great trauma in her past or some Dead Little Sister she's replacing, it's just how she is, and always has been. All she wants is to be accepted for who she is, and it hurts her terribly when the main character, the one person she thought would be her friend and accept her no matter what, is... well, a jerk about it (for example, his first act when he finds out she's "really a boy" is to force her to cut her hair to look more boyish, even though the idea upsets her to the point of crying over it). That being said, she still loves him no matter how badly he treats her, which is frustrating.
But who am I kidding — most people who would even consider reading this manga probably don't care about any of that. And I can't even recommend it to the people who do care about that — if you really want a good manga about MTF characters, go read Double House instead. On the other hand, if what you really want is a mostly-generic seinen romantic comedy with a slight twist, this would fit that bill quite nicely. Though there are probably other ones out there with nicer art and main characters that you won't want to punch in the face (well, maybe that's just me).
Manga It sucks, but I'm going to recommend it anyway
I agree with the review below me, however I'm still going to recommned No Bra, not because it is hilariously bad, or because it's actually better than it sounds, but because it gives a good frame of reference to how bad the indecisive, spineless and completely bland male lead in Harem stories could be. I didn't initially like Tsukune in Rosario+Vampire because he had next to no personality, no interests and was there solely for the reader to self-insert, but at the very least I could say that he never had malicious intentions whenever he hurt others and was honestly trying to do the right thing.
Masoto, however, is a unexcused dickbag, he is selfish, oversexed, lying, unfaithful and a Karma Houdini. This would at least be a good series if the author intended masoto to be a jackass who ends up living an empty life because all his relationships are based off of lies. But this isn't the case; Masoto only tells everyone the truth he should have told them right away, only after he's spent his good time using the lies to get him 2 women (well sorta) romantically involved with him. Then he ends up looking like the good guy because Yuki and Oozora don't know that he has kept the truth hidden long enough to manipulate and exploit their misplaced feelings for him. Only the reader knows that this guy is a completely selfish asshole without an altruistic bone in his body. Yet the women see him as an honest, caring and nice gentleman because their perception of reality is shrouded in lies. So Masoto ends up with the girl of his dreams and is vindicated by history despite being transphobic, cheating, attempting to have sex with someone who was drunk and lies of omission to Yuki and Oozora that cause them to fall for him. The worst part of this is that in the end, he was still bland as Tsukune was in the earlier volumes of Rosario+Vampire.
And while the lesson Yuki learned at the end was a good message. The all that is overrided by the fact that the Characters all have flaws that are never actually addressed as flaws and no one gets anything close to what they deserve, the nice people are manipulated and the jackass gets the girl.
I still recommend it because it made me realize that the bottom of the barrel, could me be so much worse.