Hi Brennan! Prefect is licensed under Apache V2, you can read more
here. This means it is free & legal to use Prefect OSS in an enterprise setting.
There are some key feature differentiators between using a Prefect server and managing it yourself, vs using Prefect Cloud. You can see Prefect Cloud specific features & functionality
in the docs.
Of note for an Enterprise are security-related items like users/authentication/permissions/workspaces/service accounts/SSO/etc. There's also some other feature-specific differences like Automations & API Rate Limits.