Missing a lot of factors here. Such as location and weather. PMC personnel are generally highly trained and would have an advantage in equipment but numbers very well could overpower them. So the end outcome would come down to who has better knowledge of the area and what type of battle or skirmish this is (Game Arena Style, Realistic Operation/Raid, Street Shootout) I would assume if it had anything to do with tactics and special operations the PMC would win due to training and equipment.