Montivideo is a pretty city, however, crime is a big problem. Police are everywhere and if you wander off the main walking street, you do so at your own risk. We heard of two incidents where peoples bags were almost stolen. While Montivedo has interesting buildings, there isn't much to do or see there. I would have preferred skipping it and spending two days in other ports where there is more nature and activities to do.
Punta Del Este, Uruguay - isn't on the port list of Cruise Critic for some reason. This port is a beach resort. Things are over priced and not much to see or do here. Again I would have preferred more time in other ports further South.