XML gateway or bespoke

Hello Experts

We are using tradex as the hub for inbound invoices and PO outbound. We transmit the purchase orders to Tradex on a daily basis and Tradex will validate the invoices against those purchase orders and send across the invoices in what ever the format we like. Now the decision to make is to use either XML gateway or a piece of custom code to convert and use API to create AP invoices. I have gone through some of the documents and got even more confused as there are pros and cons of both the options.

With XML Gateway the feed can be real time and there will not be any security and performance issues however it requires more configuration and maintenance.