Article has hands on impressions of all organization XIII members in KH 358/2 Days.
From Siliconera: I quickly realized that the character you choose in Mission Mode is going to be based largely on the way you play Kingdom Hearts: 358/2 Days. Some present a larger challenge than others. Some characters use brute force while others make better magic users. And then, there are some that are just plain hard to use.
Here are my initial impressions of the 13 members of Organization XIII in combat. Keep in mind, these are just my personal opinions, and a character that didn't work for me might end up becoming your favorite.
1. Xemnas: He may be first on the list, but he's the last character I tried using. His stats are generally above average, compared to the other members as a whole. Unfortunately, he doesn't have that same pizazz that Xigbar, Xaldin, Lexaeus and even Luxord or Vexen have. He's a great character who works well in practically every situation, but just not all that special. I thought he was good, but I didn't think he was great. Especially since his combo only lands three hits.