Just finishing up a long layover and while killing some time on a rainy day, checked the bank withdraws (as posted electronically by my bank) vis the cash I pulled from the ATM's here in Campinas. Found an interesting fact about one of the US banks with cash machines I used here two weeks ago. After doing a conversion of Reals to USD, found that the Chase Bank ATM I used charged $5 for the privilege of using them. In contrast, the ATM I used out at the airport this trip did not charge a fee. I didn't keep the slip from the previous ATM usage but it seems clear that, at least in Brazil, stay clear of Chase when exchanging money.
Checked several exchanges I did in France and UK this summer and found I got excellent value, re: very low % difference when using the dollar rate at the time of transaction. I used the online Oanda.com converter.
Anyone with good intel re: ATM's or particular banks to avoid and where, feel free to share.