My MIL took her Natwest switch card to WDW in Feb with mixed sucess. Some bank machines would take it and others woudn't. It has to display the Cirrus logo or forget it. Same goes for shops - she was refused more than once and ended up taking large amounts of cash out of the ATM's that would give it to her. Not a great idea, security wise.
We have always used our Delta card which has a visa logo with no problems, although you are sometimes asked to type your pin number into a little machine before it will authorise.
My advice would be to either take TC's or maybe consider taking out a credit card before you go then paying it off when you`get home, followed immediately by a 'cutting up' ceremony!