Best: Definitely agree with Matoya, who is not only a great reference to the first Final Fantasy, but was a character that you don't even expect coming and she ends up being awesome. But I also have to give big props to Haurchefant, even though he's not a new addition. His trust and loyalty towards the Warrior of Light makes the journey to Ishgard go smoothly, and he was just about the only character from the outset that didn't seem like he was gonna stab you in the back at some point.

Worst: That one Vanu-Vanu that makes you kill Imperials three times. Seriously, to hell with that bastard.