Banco Nacion is a good place... if you want to perhaps get an additional AR$1 per Dollar, you could also try to exchange currency on the Blue Market. Depending on how long your stay in EZE is, you may want to spread out your currency trades as three is a possibility the Blue Rate will see some movement after December 10th - when the recently elected government takes office. Nothing is for certain, a lot is very much up in the air.... and certainly nothing to lose sleep over, but as I write above, it all depends on how long your trip in Argentina will last and what you plan to do in terms of shopping & other activities. Cash is King in Argentina so I suggest you bring a pile of Ben Franklins and keep your options open.

You have PM.

Cheers,
Alex / Gaucho100K