I'm not sure why so many use the cambios when ATMs will give a better rate.

There are banks that have no ATM fees AND refund any fees charged if you use an out of network ATM.

When I use my TD Bank ATM card, I get money exchanged using up to the minute rates, no fees, no charges. Beats the cambio every time. If you're getting less than 110 JA for every $1 USD, you might be doing it wrong.