Rio de Janeiro
We spent 4 days in Rio before the cruise, one on the ship while overnighting. Rio is amazing and I recommend it to all. We did have a private guide for two days, and I also recommend this since it's a bit daunting, what with the stories about safety and poverty, the language, and the traffic. We stayed in Ipanema, an area that I highly recommend. It is a bustling, comfortable residential area that felt very safe, but is also lots of fun. We went to a tiny club playing Bossa Nova music one night, which was awesome, and made up for our less than stellar experience at Cidade de Samba (Samba City), which was less than stellar.
I'll mention the other Brazilian ports here as well. Salvador de Bahia is a beautiful old crumbling place. It's been made a UNESCO World Heritage Site, and I can see why. But I think they may have left it too late--buildings really are crumbling and many seem beyond compare. And the hot, humid climate makes upkeep a constant activity. I will watch and see if they manage to restore this city, but probably would not go back.
Fortaleza was a brief stop, with just a bus shuttle into the market to shop for a while. So did not see much. It also is very hot and humid, but seemed less so than Salvador. The beaches looked beautiful, and there is lots of money flowing into this town with many new luxury condos and hotels.