As flight crew rather than cabin crew, I've experienced aircraft evacuation on stand (fire on start up) and away from the terminal. The evacuation on stand was far more difficult to manage. It seemed that the dispatchers/ground handlers hadn't been trained to consider/deal with that scenario (should they be?) and because we were on stand, there was more opportunity/temptation for the pax to wander off around a dangerous area. Away from the terminal, the pax remained in a group, treated the situation more seriously and the emergency services/airport authorities dealt with them on arrival.