*I'm including Roxas, and Riku if you don't mind.*
Style-Wise
1.Sora/Roxas: Just look at KH2, and try and tell me that's not awesome!
2.Ventus: It's fast, stylish, and the Finish Commands just great!
3.Aqua: The attacks don't really entertain me, but her FC's are the best out of all of them.
4.Riku: You can only play him in KH: Com, and Days, but when your playing as Dark Riku, it's just.....Wonderful.
5.Terra: Even though it his combo's don't have alot of variety, he still is fun to play as.
Play-Wise
1.Sora/Roxas: Still number one.
2.Terra: He can kill anyone in two hits(Except VLS, and MF)
3.Ventus: He can do pretty good at defeating enemies.
4.Riku: Love his moves, but.....
5.Aqua: Great style, awesome character, but really all your doing is spamming Magic attacks.
Also this is my opinion, and I respect anyone elses opinion's. Feel free to hate on my choices if you want.