Hi ,
I think using a visa Card abroad is a very bad idea for the following reasons
(a) you will be charged a Commission (of between 1 and 3 %) for each transaction
(b) the exchange the Visa Card Company uses is a very bad one which could be much worse than what the banks give .
(c) Your card could be skimmed
(d) Also i remember seeing on this site that if you load up with cash on your CC and it is stolen you will have a hell of a time trying to get the money back from the Visa Card Company ,if all the cash you put into the card is used by the criminal.
So personally i think using a Visa Card is a very very bad idea.