Both... I have multiple doctors in my family that work in the system so I get to hear a pretty good account of what things are like. In an emergency you will not have a choice which hospital you go to as well. Its sad but the reality of a system that lacks funds and planning. I am fully aware there are some great hospitals in Buenos Aires that could nearly complete with the best but in general the quality is low albeit 'free' if you are willing to wait 24 hours in a waiting room and see a doctor who is clearly overworked and underpaid and lacks the tools and medicines he/she may require. Its like expecting a 5 course michelin star meal from a free food truck for the homeless.
In the US, people wait for hours in emergency rooms - then an intern looks them over and refers them to a specialist, who generally has no appointments open for at least three months. That is for people with good medical insurance. I shudder to think what happens to those without it.
Like yourself, I have many close relatives who are physicians and surgeons - my father, a brother, a sister, seven cousins, and three uncles. Several of them did their post graduate training in US and German hospitals.
Their unanimous opinion is that doctors here can hold their own against those in any other country. Sadly, Argentina still lags behind when it comes to support systems available in other places: enough nurses, technicians, etc.
It is true that doctors in public hospitals are underpaid, but keep in mind that medicine here is largely a vocation, not a business as it is in the USA. Many doctors with lucrative private practices work part time in public hospitals, because it is their calling. Most of them take care of relatives, friends, and friends' relatives for free.