I have worked for several women and several men. I have had ineffectual leaders of both gender. Usually it's for the same reason, they attempted to lead through fear. Or they attempt to manage to the group and not the individual.
A great leader manages positively to the group and when necessary manages negative aspects to the individual.
I can say that most of my women leaders have definitely been better at this than the men. They've tended to be more "nurturing", I know it's a cliche but it's true. At first this always annoys me but then I grow to really appreciate it. Women more often than men actually care about their employees well being while the men care more about how their employees can benefit their own well being.
All generalizations based on my own experience. -Take with many grains of salt.
I have had 2 leaders that I've really enjoyed and learned from. A man and a woman. I would gladly sit down to dinner with either and share a bottle of wine. -That's my kind of leader one that I would voluntarily spend time with.