If you wish to copy ALL the users and roles/profiles from one system to another, and totally replace the users and roles/profiles in the destination system, then you can do a remote user master client copy. This will only copy the user accounts, roles, and profiles. (Tcodes SCC9).
Another option would to perform a user master export and import using SCC8.
If however you have users and roles in the destination system that you need to keep, then it would be best to recreate the accounts manually (or using CATT ..etc..), and just "download" all the roles via PFCG, and upload them in your destination system.