From the name, you would instantly assume that this story is hentai. Could not be less true. In fact, a date with rosie palms is little more than a device that lets the story go through its main theme, the socialization and relationships between vindictive students.
It's difficult to describe what exactly this manga is about without giving it all away. The character development is incredibly deep (if a shonen battle manga had the character development of a kiddy pool, this is probably closer to the Marianas Trench). Considering the length of the work, the main character undergoes some incredible attitude changes (in part due to aggressive use of time skip over months of school).
In short: there's little to say about this manga that doesn't spoil it entirely. But it is good, and the characters, although not entirely likable, are well within reason. Not much to say, but read it and you won't be disappointed.