What Mark means is that MasterCard and Visa are accepted in more places than Maestro and V-Pay are. That may certainly be true, but I personally haven't seen a shop that does accept MasterCard but not Maestro.
As for the Netherlands, where I live, Maestro is accepted almost everywhere (because that's the card issued by every Dutch bank) whereas MasterCard/Visa acceptance is not at all commonplace. It's the exception, not the rule, to be able to pay using a MasterCard or Visa. Although acceptance is growing, you do still need to have Maestro around here.