Main advantages of Plone include scalability, user management and security for large and small websites. For larger sites, Plone delivers an easy multi-server setup and works well with multi-language sites.
Plone’s user/permission management (users, groups, permissions, multi-tiered access to resources, content workflow) capabilities are the most robust and flexible of any CMS. Regarding security, the Plone/Zope/Python combination has had fewer security flaws in recent years than Drupal/PHP or WordPress/PHP.
Plone also has a large and active development community with benefits including: