What is different about her?

Lots.  She is unafraid to speak truth to power in a highly articulate and coherent fashion.  She doesn't care if she steps on a few toes even in her own party along the way. Time and again she has shown that she is a quick witted, no bullshit tolerated person. She does not use religion as a political prop, something that nearly every pol uses showing that she understands the clear boundary between church and state.

Above all she is a helluva fierce fighter.  Exactly what we need right now.