Admin - universal permissions, security and user management
Developer - access to all entities under Apps in the ribbon of the web console, along with destinations (note that this role does NOT include template creation/editing)
NewsStand user - ability to receive reports (subscribing is a separate permission)
User - same permissions as Newsstand User but not locked so you can configure them as needed.
If you want to see the exact permissions, click on the role in the Admin > Security roles section.
Go to Roles in you admin console and look at the templates for pre-existing Roles. You will see exactly what options are selected for each role, meaning what user whitch such role can do with NPrinting.
look at screenshots how to observe setting for each role. Difference between each role is self explanatory then. You can use those roles as a template and modify them when creating new roles.