While a prepaid card is probably safer, you will almost certainly get a better deal by converting to cash at the right place.

All those prepaid money cards are OK - but they quietly sting you on the exchange rate. If you shop around, you will see there is some variance on any given time about what rate you will get. This includes cash too, but you can probably get a better rate for cash.

When I went to the US a few weeks ago we took a couple of thousand on a prepaid money card, about $1000 in cash and credit cards.

Cash was the best deal. I got a rate nearly 3c better than than my bank would do for either cash or the debit card. Was a small independent kiosk about 3 doors down from my bank.

Be very careful with using a credit card and know your cards fee structure. Many cards have stopped waiving the cash advance fee even if you have a positive balance, and many banks add a fee of between 1-4% for purchases on top of the Visa or MasterCard exchange rate (which already has a commission component).

The other thing about taking a CC with a positive balance, is that it may not stay positive for long. Say you take a card that is $3k in credit. When you arrive you grab a rental car and check into your hotel. All of a sudden you have $3k in holds on your card, and when you go to the ATM and withdraw money, you're no longer in credit and incurring not only a cash advance fee on your withdrawal, but interest from the moment you get that money out (No interest free period on cash withdrawals).

For us, we could have got the best deal by taking all cash - but there was a balance between getting a good deal and the risks involved with large amounts of cash, so we did $1000ish cash, $2000ish prepaid debit card (Which we then used mostly for in store purchases directly, with 1 or 2 cash withdrawals as the initial amount ran on). There was a small amount over the top of that that went on the credit card. We didn't want to convert more cash than we needed (and then have to pay to covert it back later). But the CC was the least 'cheap' way of doing it, as after you pay the currency conversion fees, the converted rate is a bit worse than the cash rate. But easier to pay the CC when we got home than have to convert unused money back