Monster High is GI Joe, Pokemon, Transformers, Ninja Turtles, She-Ra, He-Man etc. It follows the same formula by and large:
-Wide cast of characters
-Everything that pertains to the characters (accessories, outfit) are very uniquely them
-Everyone can have a favorite
-Even the "villains" are interesting and dynamic
-The opposite gender is short-packed and worth the most (male dolls, in this case)
It's a girl's toy line...with dresses and combable hair. But it's really articulated like an action figure line.