Looking at the two itineraries, it seems the only difference is that you spend 2 more days in Antarctic waters. The trip down looks the same and the trip back also looks the same. Since the weather can be finicky, more days gives you more opportunities to get ashore if the weather doesn't cooperate. So, if you can afford it, it would seem the longer trip would be better. BTW, the map is deliberately vague, since the landing locations can vary from trip to trip.