I need to transfer over 1 Tb of data from a share on an ext3 file system that our corporate office uses. The share contains files with different owners and groups and needs to be copied over maintaining these permissions.
After experimenting with this, I have found that the best way to achieve this is to mount the SAMBA shares in Windows Server, and use Robocopy to sync the files. It will do a mirror copy if you want it to. It's a very robust file copy tool in windows (later versions) I knew nothing about prior to today.
In fact, it has a /SECFIX option that will fix security information on files already copied. I am testing this functionality against a rsync copy made of the ext3 fs we are moving. With any luck, before days end I will have a complete up to date copy of the corporate share including correct ownership and permissions!