Couple of weeks ago when I was in Vienna, the only DCC prompt I ran into was with Bank Austria:



I personally found the prompt "the amount is always paid in EUR including exchange fees at 6,00%" - at first I thought it meant that if you choose EUR, that they will charge you 6%, otherwise you pay in USD at the craptastic exchange rate.

HSBC ended up only billing me $21.95 that day, so it was a full 6% difference.