Do you mean the pre-paid currency cards that you load up with euros or dollers and use just like a debit/credit card? If so, then yes we've used them for a few years now.
Used the Co-op's Cash Passport Euro card in France the year before last, a Fairfx Dollar card in Florida last year and then a Fairfx Euro card in France this year.
Had no problems with them at all. They were accepted everywhere that accepted Visa/Mastercard so was just like using a credit/debit card.
The only downside in using the Fairfx one (can't remember if it was the same with the Cash Passpot one) is that the only way to check your balance was online, which is a pain if you haven't got a internet connection.
As for charges, there wasn't any charge for actually using it in shops etc, but there was a charge if you used it to take cash out of a machine (just a couple of euros/dollars) so tried not to use it too often for cash.
The other thing you need to check to avoid charges is the inactivity fee. With the Cash Passport they charge you if you don't use it for so many months. We just cancelled the card at the end of the holiday, but with Fairfx they don't charge if you don't use the card so we have kept our Fairfx cards and will use them again for other holidays.
hth
Luv Suzy
