To exchange they charge a flat fee - $3 for Amex members, $4 for non-members - sounds great, right? But they make it up for themselves by giving you a rather poor exchange rate. I exchanged US for Canada - they gave me 1:1, when the published exchange rate was 1:1.07, so effectively they charged me 7% in addition to the flat fee. The booth at the airport would have given me better value! I just exchanged a little bit and then used the ATM in Canada to get the rest that I needed.