I've only read about his first regime (40s and 50s), so I can't say much about the 70s.
He led a military coup that had massive popular support due to intense hatred of the previous, which just carried out the irrational whims of a quite ostentatious ruling class. The working class went from poverty to relative wealth and security as the government nationalized foreign/imperialist owned companies and implemented basically Keynesian policies.
It worked incredibly well and took Argentina from massive debts to become a creditor nation. The imperial nations couldn't do much because during this period they were in the worst of WWII.
After the war ended, the imperial nations took revenge on the nationalizations so they put significant pressure on Peron to repatriate all relevant industries, including ones formerly held by Nazi Germany. At this point, several European nations founded the Paris Club, which has been negotiating debt with Latin America ever since.
Peron, to maintain his regime, began to break strikes and enforce austerity measure on his strongest constituency: workers. By the early 1950s he had lost most popular support and the coup that overthrew him was just tearing down an already rotting building.
tl;dr
Peron was a dictator that seemed basically benevolent when no one was pressuring him, but he turned against the working class to safeguard his power the second he ran into trouble.
Also, Borges was probably right about Eva, but he's still a dickhead.