I'm fond of using these three too. Starrk is just a beast with his Square attacks.
I agree, very easy to get combos with, and I've never lost once with him...Unless it's a time attack mission or something that doesn't require his strength.
Not tried all of the characters yet, but at the moment it's all about Barragan (respira is pure haxx and his ignition mode just owns anyone who gets near) Starrk and Shunsui