iNetSudo for SugarCRM 8.0+ and 9.0+ allows SugarCRM Administrators to easily change to a different user without knowing their password, enabling them to configure and test any user's experience.
Other add-ons of interest
Dashboard Copy Manager
Administrators can copy dashboards from any user to any number of users, teams, or roles. Save time logging in as individual users to set up their dashboards.