Honestly, nothing was all that unique in this one. It was a typical light novel adaptation and on top of that, one that has been done several times already. That being said, it entertained me, and that is what I think is the most important.
In all seriousness though, the characters weren't unique, the concept had been done before, and the story wasn't anything special. It's a typical harem/ecchi anime though, so what would you really expect from it? The fights became pretty decent after a while, and although it seems like the story could continue, the MC does appear to choose one of the girls, which is unusual for this kind of setting.