User blog comment:Zwann/Vasto Lordes in the Espada/@comment-4907633-20130912004543

Well, Harribel was like any other female hollow, weaker. She was an obvious Vasto Lorde, yet she seemed quite weak compared to some of the other Espada. She even had a hard time against the Hammerhead Espada when she was still a Vasto Lorde. It's obvious that usually Arrancar are more powerful than a Vasto Lorde, but maybe not by too much.