Okay, to start, if you don't like quite extreme nudity or the harem genre, you should search for another anime to watch. Even if you like panty shots or stuff like that, but don't like nude boobs etc. you shouldn't watch this Anime.
Personally i loved Sekirei, cause the plot of most Harem/Ecchi anime is terrible, however in Sekirei, the plot is well-thought and exciting. The story starts right of the bat, and doesn't stop at any point.
I won't go around spoiling the whole Anime, but you should be prepared for a lot of girls fighting for 1 guy, a guy who can be a douchebag at some point. That is the only thing I didn't like about it.
So, You should watch it if you like bouncing boobs for no reason, and if you like an anime with a good plot line, i highly recommend you this one.
