You could fill books writing pros and cons of that. You have to bare in mind that Peron's government increased a lot the purchasing power and the access to higher education of the working class, therefore increasing the internal market and the Argentinean talent pool. He also gave a heavy political blow to the real left by, basically, controlling the unions and gaining the support of the working classes, thus turning socialist, communists and anarchist groups in nothing else than far smaller and rather intelectual groups. Without Peron, Argentina might very have ended up with an Allende like figure.
Of course Peron has plenty of cons such as his authoritarism, the extremely strong division he left in the Argentinean politics, impulsing non-profitable industries, attaching the unions to a political party, the personality cult, etc
Although he increase the purchasing power of the Argentines (it was just a short-term measure of Juan Peron, after 1950, Argentina's economic power starts to degenerate 'cause he discourages exports), but he didn't encouraged foreign investment in manufacturing and energy sector (he encouraged the foreign investment in oil in 1953 but the Exxon and the Royal Dutch Shell shun Argentina because Peron is not foreign investment friendly and his anti-market stance). He didn't support the heavy industry industrialization.
Peron was very erratic in terms of political stance (Peron was pro right-wing at the same time pro left-wing), that's why there's extremely strong division among the Argentines. He's very autocratic and demagogic. He use democracy to destroy democracy. He nationalise the railroad system owned by the British and the French (which at that time, the most extensive in the world). After the nationalisation of railways, Argentina's railway system began to disintegrate due to the mismagement and corruption (which Peron had tolerated).
Because of Peron's pro-Facist stand, he destroy Argentina's economy forever and he prevents Argentina to boom economically after the WWII.
If Peron didn't become a president, Argentina would be the 4th largest economy in the world and Argentina would be the 9th member of the major highly industrialized nations, US$50,000 per capita by 2008, 60 million population, and highly innovative and competitive nation in par with US, Japan, Germany, France, and UK.