My organization is currently in the beginning stages of connecting our SFDC org with Marketing Cloud. One of the discussions has been around doing a rekey of our subscribers within Marketing Cloud. I understand it will take a service engagement with Salesforce, but I want to make sure we do it correctly.
Specifically, if we have customer information SFDC, is it generally considered a best practice to have the Subscriber Key in Marketing Cloud be the Contact ID from the SFDC org, or does it matter? We want to make sure that when we connect the two clouds, we are able to have a fairly seamless back and forth communication. There were thoughts around using an internally-generated GUID in SFMC, but if this makes things more difficult in the long run, I want to avoid it.