Mine is Asuka. I'm still working on getting better with her. I started out spamming between 2 moves as a joke after getting my behind kicked trying to play as Leo online. Then I decided I really liked countering, so I went into Practice mode and learned some other combos. I like the countering because i'm horrible at timing low/high blocks against spammers, so its great to just counter them out of it. I still have not learned a single juggle with her (or any other character). I prefer to try to break other peoples spams/juggles, and then beat them with basic combos
I know what you're thinking, and it's partially true, i do suck at combos, and honestly fighting games in general haha. I have managed to get my win percentage to 47% with like 300 something wins vs 400 something losses, so i'm slowly moving up!