Ignacio Walker has a very worthwhile article in Dissent about the Latin American lefts. He is a Chilean Christian Democrat who served as Foreign Minister under Ricardo Lagos. Popular accounts generally congeal the lefts into two--pro-U.S. vs. anti-U.S., undemocratic vs. democratic, or other similar unsatisfying simplifications. Walker sees three: Marxist, populist, and social democratic. Of particular utility is how he places current politics into the Latin American historical context, e.g. "In significant ways, the history of Latin America in the last century can be described as a search for responses to the crisis of oligarchic rule that took place in the 1920s and 1930s." He has a great quote from a letter that Juan Perón sent to Carlos Ibáñez in Chile:
My dear friend: Give the people, especially the workers, all that is possible. When it seems to you that already you are giving them too much, give them more. You will see the results. Everybody will try to frighten you with the specter of an economic collapse. But all of this is a lie. There is nothing more elastic than the economy, which everyone fears so much because no one understands it.
He then discusses the ways in which populism has re-emerged in Latin America, first as neoliberal (e.g. Fujimori, often called neopopulist) and then leftist. One major point he makes is that the current strand of leftist populism came into being at a time when democracy was taking root, so is actually less authoritarian than its predecessors. Nonetheless, there is always a tension between the personalization of populist rule and representative democracy.
At the same time, however, his focus on populism means that he does not discuss his "Marxist" category adequately. He views Chávez as both populist and Marxist, but it's not clear whether he would label anyone else (except the obvious example of the Castros) in that manner. Regardless, given how much latitude Chávez gives capitalism, I'm not sure Marxist is a good way to describe him. He mentions factions of the FSLN, FMLN, and the PT but the dominant tendencies of these parties are no longer Marxist.
At the very least, it is a step forward from the "bad left" vs. "good left" that we normally see.