Maintain permissions while migrating to a new server

q: What's the best way to copy all the files from an old server to a new one while maintaining permissions?

a: We've found robocopy is the best to accomplish that.  Here is a sample format we have used repeatedly with success.

robocopy \\fileserver\users D:\ServerFolders\Users /E /DCOPY:T /SEC /MT /V /TEE /NP /LOG:20150514_Ddrive.log