The cruise from Rio de Janiero to Santiago was really quite beautiful and included several interesting stops. We arrived in Rio 3 days early since it was near Carnival and we wanted to experience the atmosphere. We stayed at the Marriott on Copacabana and felt perfectly safe. We did follow the usual rules concerning jewelry (none) and leaving money and passports in the hotel safe. They close down half of Avenida Atlantica on Sundays and strolling down it is a wonderful way to get to see the Brazilian people at play. Lots of families. As you get to Ipanema Beach it becomes a much younger crowd. Food was surprisingly expensive and we did tire of all the meat all the time. But it was tasty. We tried feijodas, the national Brazilian dish of beans and meat, and it was delicious. However, one order would serve several people!
Going up to see Christ the Redeemer was the highlight of our Rio experience. Be sure to get there first thing in the morning so you can get pictures w/o hordes of people. The views from there were magnificent. I'm not sure I would do Sugarloaf again. It takes forever to get up there (2 separate trams -each with their own line) and all you see are the beaches.
From Rio we flew to Iguassu, Brazil and stayed at the Hotel das Cataratas, the only hotel on the grounds of the national park. It was a huge place and there was a lot of walking involved - just getting to your room. It was nice to be able to go for a walk back to the falls after hours (which one of our group did) but I was way too tired for that. The Falls themselves are spectacular! And the walkways bring you very close to the largest ones. You will get a bit wet from the spray but it's incredible. Much bigger than Niagara. We also did a great Zodiac boat ride on the Argentine side. To say you get drenched is an understatement but it is so much fun.
Flew back to Rio to board the ship. This was my 2nd cruise on the Star so I knew exactly what to expect. There did always seem to be people waiting to use the the exercise equipment and I don't know what they can do other than expand the area. It's unrealistic to expect to get off after only 20 minutes (which is what the signs say). The food was fine. I don't expect gourmet food on a cruise ship that feeds thousands at every meal but I think the selection is very good and the food itself is tasty. It's also easy enough to accommodate many different diets - assuming you have the willpower.
We were fortunate that the weather was perfect for sailing around Cape Horn: calm seas and 40 degree temps. It is a wonderful experience and it seemed that everyone was on deck taking pictures - even after it started raining. Next to "rounding the horn" the highlight of the cruise was sailing through the Chilean fjords. The best of it lasts about 2 hours and the scenery is incredible. Really, all the scenery along Chile was breathtaking and we were delighted to have several days at sea to enjoy it.
My only caveat about this trip is that if you go expecting that you will be able to visit Antarctica, you will most likely be disappointed. I don't believe any of the cruises this year succeeded. It's also a VERY expensive excursion but there were still plenty of people who were hoping. Otherwise, this is a wonderful cruise to a region that not many people get to visit.