If you look at it in an isolated way- I wouldn't put anyone over the other (Melania doesn't count. She seems to be completely disengaged from anything that would normally constitute the First Lady role except on the most superficial level.) But...Wouldn't you consider this on a more comprehensive level? Hillary was first in the White House where she was exposed to many leaders- nationally and internationally, had to form alliances, deal with protocol, go out and be an 'ambassador' for many things. She then progressed to the Senate where she did the usual things, then Sec of State where she again had to deal with people on a national and international level in some very sticky situations. Having been in all 3 roles would make her more well rounded and likely to see nuances than the others.
