The plot isn't too crazy: parallel worlds, bad guys that enter the human realm and have the potential to kill or kidnap people, and a defense force that is made up exclusively of women because they are the only ones with abilities in this universe to oppose the bad guys. But, surprise! Even though he is a man, the MC is involved in something :P
I promise there aren't many fanservice scenes in this show; either I'm dreaming or I remember the manga having a ton of them. Furthermore, because Kyouka has to give Yuuki something every time she uses her slave powers, this content isn't overly insistent for the sole purpose of fanservice or ecchi content. Rather, it serves a purpose in the plot.
Although the animation studio is not among the most prominent, it was still done fairly well for modern anime, with some decent CGI used occasionally that didn't look out of place unlike some other shows.
I only heard the opening and ending themes once, and consequently skipped them the first time I watched an episode, so I can't really comment on the soundtrack.
