what kind of permission details do you mean? can you show me a printscreen of those details?
Please try: Get-ViPermission | Export-CSV “C:\Temp\Rights.csv" in PowerCLI
Permission usage, under vSphere client -> Home->Administration->Roles or under vSphere Web Client Home->Administration->Roles is a list of usage elements for every user. Seems in every pages it couldn't be possible to export this list as a csv. The only way is from entities... But you should do a multiple extractaction per folder, per host, per resource... etc
Using Powercli try this http://www.virtu-al.net/2009/06/15/vsphere-permissions-export-import-part-1/