Listen, they all suck. And I am not using the term lightly. They suck. They suck so bad that every time I return to the US, I get amazed at how AMAZINGLY GOOD T-Mobile is in comparison. Take a moment to digest what I just wrote. Deciding between Claro, Movistar and personal is akin of having to decide between being beaten with a lead pipe, a baseball bat or a sledge hammer.
So, the correct question should be: Which carrier in Argentina sucks less?
Well, in this case, it is my personal experience that Claro sucks slightly less. Not by much, I tell you, but Claro makes me want to throw my phone against the wall a little less often than the rest. But don't worry too much about which carrier you end up picking. Whatever your final choice is, you are guaranteed to experience extreme frustration with the lousy services and the high prices. So relax, and just pick whichever you feel like....