Ugh I don't think I could pick, I'm way too indecisive. I know some people who found Yuna annoying, but I think one of the many reasons I love her is that while she's pretty much nice to everyone all the time, she actually manages to not be obnoxious about it. I think it's because both she and Braska are somewhat reserved in how they show their love for people - not closed, but they don't go around shoving it on people who don't want it either. And also because unlike pretty much every other quiet, polite, kind female character, you never have to rescue her. Even at the wedding, when Tidus is like 'oh noes we have to save Yuna!!1!', you get up there...and discover she already had a plan. She's not helpless, and while she's a little naive at the beginning, she definitely grows out of it. That's one of the things I really like about writing Braska - he's idealistic, but at the same time still acknowledges the world as it is. He just believes he can change it for the better.

tl;dr - OH MY GOD I LOVE THIS GAME.