Odoo Enterprise is the commercial edition of Odoo: the open-source Community core plus proprietary Enterprise applications and features, sold as a per-user subscription that includes access to the official database upgrade service, Odoo S.A. support and hosting on Odoo Online or Odoo.sh. It runs on the same framework as Community, so custom modules, OCA modules and integrations work on both.
Enterprise is the right choice when the business depends on specific Enterprise applications, wants an official subscription and support relationship with Odoo S.A., or values Odoo.sh's managed hosting and upgrade path. It isn't automatically better: a business that would use none of the Enterprise-only apps is paying a subscription for the upgrade service and the support contract.
Most of our Enterprise clients chose it for a handful of concrete reasons (accounting depth, Odoo.sh, Studio or Documents) and we help make that list explicit before the licence is bought.