What are the different sources?

There are four different types of import sources.  We typically recommend using either a Salesforce report or a list view.

List View
‍Pros - Easy to use, and you will often have them set up.
Cons - You will be limited to one Salesforce Object.

‍Report
‍Pros - Easy to use, and you will often have them set up. They can work across objects.
Cons - You are limited to 50,000 records per import.

‍Campaigns
‍Pros - It is useful if you have a defined Salesforce campaign and campaign members.
Cons - You are limited to a single Salesforce campaign.

‍SOQL
‍Pros - Provides a high level of flexibility.
Cons - Requires a person with development skills to set up and maintain.