It's smutty, violent, and pretty much pointless. But I liked it. Don't read this manga expecting to see some romantic couple overcoming the odds in a tricky situation. The semes are assholes and the ukes are idiots, it's as simple as that. And that's even with two completely unconnected stories making up Bi no Isu. Different plots, but the cruelness remains in both.
But here are some things that are good about it:
-Men who look like men, albeit not macho men, in the first half. Some even have facial hair and tattoos.
-Really hot interactions between characters, if you're okay with rough sex.
-First yaoi I've read that
opened with a yakuza (Japanese mafia) torture scene. Certainly caught my attention.
-Interesting character dynamics, in that they're completely screwy. How will the semes next abuse their partners? Will they both survive it? How much blood and/or screaming will ensue? And why are the ukes so hopelessly in love?
If there was actual plot outside of the relationships, I missed it. The second story (chapters 4 & 5) wasn't as good as the first, in my opinion. Too much psychological trauma involved. But if you like watching messed up relationships with lots of sex and abuse, this might suit you well.