My money is on the Persona 2 team. Not only does the group have some far more experienced adults that can summon their Personae any time, they all have the ability to switch which Persona they use at any given time. Between Maya, Tatsuya, Eikichi, Jun, Lisa, Katsuya, Baofu, and Ulala, the other groups don't exactly have an advantage in numbers. Taking down
Nyarlathotep]] doesn't hurt their case, either.