I chose it based on "Cruise Critic" reviews of all the companies that had sailed to Antarctica during the previous season. Ponant was rated as one of the leaders (#2 in small ship cruises to Antarctica). Also I was not asked to pay a single supplement. These two points made it very attractive.
The timing of the cruise was also correct for me as I was on vacation in November elsewhere and I intend to travel again in late January.
I was atracted by the itinerary of the cruise and the expertise and knowledge of the guides. I also had the opportunity to explore Buenos Aires and Iguazu Falls before flying to the cruise terminal.