On the MasterCard side, MasterCard has chosen a slightly different path. They've brought the cost down of processing the transaction. Their assessment fees are now actually lower than Interac's, which is positive for the merchants, but their method is a bit different in that the banks are instructing us where to send the cards, as opposed to the individual cardholder, so the banks are making the decision.
From a merchant perspective, at this point it actually matters less. In fact, in some cases, if they hold true to keeping the assessment fee at a competitive advantage versus Interac, it'll actually be a good thing for the merchants to the extent that they're billed on an assessment fee basis.