I would have to agree. Even without the orbalisks, Bane is superior in saber combat(beat Sith weapons master) and his knowledge is extensive.
Caedus would give a run for his money and probably try to make a tactical withdraw, but Bane would hunt him and kill him. Zannah could probably beat Caedus as well(with difficulty).
I don't know, I wasn't that impressed with Zannah to tell the truth. I mean, she struggle's with 1 Jedi whilst Bane takes on 3. Her impregnable shield technique might work well against the idiocy of Caedus though, and he'll probably tire quickly due to the myriad of wounds that he always sports.
However, I'm not sure how effective her Sith magic would be. On the one hand I don't think Caedus has ever faced actual Sith sorcery but on the other he has spent alot of time learning about illusions.
I think she'd do fine against Caedus for the simple fact that when Bane thought she betrayed him, he attacked and almost lost control due to the orbalisks he still had on. She was able to hold her own for a few seconds and that is impressive against Bane with the orbalisks.
Caedus hasn't dealt with sorcery, but he DOES know illusions. He might be able to block it, but she'd definitely give him a run for his money.