The same fighting girls who can kick ass, and the same kind of harem where guy is involve and quite frankly both anime are not for the conservative ones, and it's only for those who are after the entertainment side of it.
Both have the same, martial arts, fantasy, ecchi and shoujo genre.
Both have the same fighting chicks who can kick ass.
Both have the same panty shots.
Both have certain characters who is the weak link of the group.
One has more intense ecchi than the other one.
The weak link was girl in one anime while in the other anime it is a dude.
One has an extra yuri genre while the other has harem and romance as its extra genre.
-Same sort of romance/harem type of anime
-Has another character that has her own type of "Hysteria Mode"
-Similar taste of sword fighting, etc.
-Similar character traits shared among the main male characters: such as how they desire a "regular life", etc...
-Full of echi
-And finally, both anime share many characters with each other that have similar traits/behaviours.