I just went to 1563 Serrano on 25/9 and got 72,500 pesos per $100. The cashier was very friendly and courteous. Very convenient as it was only 3.5 blocks from the Mine Hotel where we are staying.
Thanks Buy/Sell for the brilliant trip report and I definitely use the cueva at Serrano 1563 as my first exchange of $100 USD after my arrival at Palermo Soho.
I was worried about not having local currency upon landing at EZE but knowing that cueva is only 400m from my hotel just made my day...