Differences Between Subscribe and Create

From API Documentation

You can use either the subscribe call or the create call to create the objects associated with a subscription (accounts, contacts, and so on). There are differences between these calls, however, and some situations are better for one or the other.

• The subscribe call bundles up all the information you need for a subscription. It is best used to create new subscriptions when you have all the information you need.
• The create call is more useful when you want to develop in stages; for example, if you want to first create an account, then a contact, and so on. If you don't have all the information available, use create. To create a subscription, you must activate the account from Draft status to Active by calling the subscribe() API.

For either call, subscribe or create, you can use the query, update, and delete calls (as supported) on the objects you have created.