Beaten Bart 2 in Oerba in my very first Try in my NCU Challenge. Actually, this was only a try for practice to see how the mechanics and tactic are working. I was very suprised and a little shocked.
After all the frustration with him along several forums, i expect it much more difficult. Used Snow, Fang and Vanille. All with magic raising weapons. Fang and Vanille kept Slow and Deshell on him with a MAN-MAN-RAV paradigm. This paradigm raised the stagger gauge too. When Bart was staggerd, i switched between COM-RAV-RAV and COM-COM-MED. I used SEN-SEN-MED for his area attacks and for healing.
Basically, that was everything i did. He fall after 8 minutes and 29 seconds.
Ohh, almost forgotten. I summoned Bahamut at his first Apoptosis. In that way, only Fang loses all her buffs, the other two kept them the full time. That was a huge advantage.