I have been on eight cruises and have cruised with Royal Caribbean, Norwegian, Carnival, Costa, and Viking River. All have been great. This MSC cruise, however, would turn anyone against cruising.
I chose this cruise because it began in Buenos Aires and featured two days in Rio de Janeiro, the two places I most wanted to see in South America. What MSC does not tell you is that this ship is operated like a hop on, hop off bus, allowing people to check in and out all along the route. This meant that the ship was in a constant state of upheaval, with passengers who were embarking and disembarking competing with cruisers trying to get on and off the ship for excursions. I don't know what went wrong on the second day in Rio, but those embarking passengers were packed into the terminal for several hours waiting to board.
Other issues with this ship: