We at Toptal initially created TopTracker payments (we don't monetize on this product at all) to be the lowest form of payments for freelancers globally by partnering with Payoneer. Essentially, it's a fixed 2% transfer cost including FX, however TransferWise is often able to beat that.

We, and I'm sure other companies, would love to partner with TransferWise, however they've yet to create API's that allows for a product to work with their system effectively. Once they do so, this will be a game changer for doing payroll globally.