Medics in mvm are like god tier.
Just use ubersaw, upgrade firing speed and health on kill.
But yourself an uber canteem, after you pop your kritz, run toward some big guys, use your uber canteen, ubersaw to full kritz, ru nand re-pop.
also upgrading heal rate and max overheal is really strong
a 750 health heavy constantly being healed at ~2 regular medics on you speed? yes please.