I'm trying to come up with some pros/cons to the following scenario. The customer is implementing Marketing Cloud. The data that Marketing Cloud needs comes from the customer's internal data warehouse. So, naturally, we suggested to bring in flat files from their data warehouse over to Salesforce Marketing Cloud FTP to import into Marketing Cloud. The customer then brought up the question "is it possible/doable to simply use Salesforce Connector to bring in ALL Marketing Cloud data into Marketing Cloud by way of Sync'd Data Extensions?" This way they won't have to drop files to the FTP every so often. What are the limitations to synchronizing data between Sales Cloud and Marketing Cloud? Has anyone done it this way with any of your clients? I'm still steering towards flat file imports since that's the way I've seen EVERY client of mine bring data into the Marketing Cloud. Thoughts on this?
There is huge difference between using flat file imports and Marketing Cloud Connector for Sales/Service Cloud.
Flat file imports are good for batch imports, and are usually not real time. If you have a normalised data model, you will either need to have a file/Data Extension, or first denormalise into a single file and then normalise the data. You can work with file drop triggers, so your automation and import activity starts instantly the second the file is dropped on SFMC SFTP.
The MC Connector not only provides you with the Synchronised Data Extensions (with max 15 min delay), but also enables you to build extensive cross-cloud journeys (triggered real time when data changes in Sales Cloud), which you can see illustrated here. If your client is already using Sales/Service Cloud for storing all their contacts, I see no better option than to proceed with integrating using the connector. You must use Lead/Contact ID as Subscriber Key if you want to utilise these features.
Please keep in mind, that if you are using the Sales Cloud in B2C context, and use both Leads and Contacts, once someone gets converted, he is synced as a Contact, using Contact ID as Subscriber Key, generating a new Subscriber Key. Hence there is currently no way of linking the historical engagement of the Subscriber with Lead ID as Subscriber Key to the new Subscriber with Contact ID.