Bahamut's actions look nice, but he looks a little overdone graphically.
Anima's overderive looks nice.. but she takes a while to summon/kill things.
Shiva is rather quick in attacking and no negatives really.
Ifrit is ok.
Ixion didn't really impress me much beyond what Shiva and Ifrit already had.
Valefor I liked a good bit. His special was rather nice at the begin... slowing attackers down and killing them by delaying their turn.

Hmm that leaves Yojimbo and the Magus Sisters

Yojimbo: IMO quite overrated for the story and scenes behind him... to end up not really being worth much.... especially having to pay him.

Magus Sisters: Passado = lots of damage, but besides that and AutoLife, their only real advantage is flashy attacks and the fact that there are 3 of them.