As I said, it's been a few years. But Santa Cruz is a dump, and not comparable in any way to Buenos Aires.

Lima has both very good areas, where the cost of living is very high, and horrendous areas (most of the city, actually).

The only places I know in Latin America with a cost of living as high as Bogota are Sao Paulo and Rio. So I'm astonished to hear Buenos Aires is in that range now, since the last time I was around there the cost of living was easily half of what you see in Brazil and Colombia.