I don't know, I didn't think it was good at all. He was very underpowered to be a final boss. Very predictable attack pattern, and he telegraphed everything making him super easy to read. It also seemed like every few hits there was a cutscene of him getting knocked down. Once you get past the "I'm fighting Vergil!" hype, there really isn't anything there that makes the fight good.
He had practically the same moves DMC3 Vergil had. Yeah, he telegraphed more, but this game was easy anyway and he wouldn't be any different. I liked the cutscenes in the middle of the fight because of the added tension, they'd always say something to each other, which I personally liked. But I understand why people wouldn't.
Aion is just like all other WoW clones, I mean, the Mage in Aion has a Fireball spell and can make Portals. WoW ANYONE??? - Aion Boards
I guess i liked the barbas fight because of the boss design. I actually had problems with the spawn baby at first because it was so boring.. But overall the bosses werent that bad. They just werent challenging enough.