David and I did that cruise in 2002 over Xmas & New Years. We had a great time. The highlights were the penguin rookeries and "Senor Tango"
(show and dinner) in B.A. It was a very relaxing cruise because of the days at sea. The Glaciers and the southern most parts of the cruise were fascinating as well. Chile is quite beautiful almost everywhere you go. Have a great cruise. (Rent the movie "Motorcycle Diaries" before you go for a taste of the scenery. It's a great flick too!
When in Chile buy some of the excellent red wines at very reasonable rates. The corkage fees/savings on board are well worth the inconvenience. The wine stewards love tasting the different wines with you at dinner time.
We'd go back again in a heartbeat but we're on a different cruise through the Panama Canal this Xmas.