She's upbeat and positive. She managed to restore at least a semblance of harmony to the camp when she became leader, in the immediate wake of the "9 against 3" scenario Duncan had fostered. She is decisive and so far her decision-making has been OK. She consults people and invites opinions, and isn't afraid to change things when it's clear the other contestants aren't happy with her choices. She has tried hard to include people, even Lady C.
I think her people management and communication skills are excellent, I'd never heard of her before this, but so far I'm impressed.
Also I doesn't hurt her chances that she's pretty in a (relatively) natural way.
She's a very clever girl.