I found Montevideo fairly safe and I stayed in Barrio Sur which is supposed to be a sketchy area. However as a whole, Montevideo is a bit too dirty and polluted for my taste. It reminds me of Eastern European cities in the late 80's, just before communism collapsed.
Uruguay has some good attributes. The food tastes better than in Argentina (or maybe I was just lucky), they have beaches and were politically more stable than Argentina, money flows easily in and out... Now, however, the people of Uruguay have decided that they want their country to be led by a communist who was a member of an organization that commited kidnappings and murders in the past. I have seen "Pepe" murals everywhere. There was also propaganda for "juventud socialista", "justicia social" and other crap. That is quite disturbing. I guess the people of Uruguay feel too wealthy and would like to try out a system that has failed miserably everywhere in the World. Uruguay also started to tax income in recent years and has some taxes that are unprecedented in other parts of the World. Anyone investing significant money in property there must be braindamaged.