Version 4.0 of the User State Migration Tool will release with Windows 7. The RC version of it is available in the Windows Automated Installation Kit for Windows 7 RC (http://www.microsoft.com/downloads/details.aspx?FamilyID=60a07e71-0acb-453a-8035-d30ead27ef72&displaylang=en). This has several new features, including one that MDT 2010 takes advantage of: hard-link migration. If you are performing a Lite Touch “refresh” deployment (backing up the user state, clearing the old OS, installing a new OS, reinstalling apps, and restoring the user state), this process can be made significantly faster using hard-link migration, taking minutes instead of hours because it doesn’t actually move any of the data. Instead, it just creates new links to the same existing files in a protected folder (e.g. C:\MININT). When the old OS cleanup process runs later, it deletes the original links but the files remain because there is still another link in the protected folder.
The “estimate” process that is executed in the task sequence recognizes that USMT 4.0 is present. When a refresh is being performed, it will skip the estimate because it knows a hard-link migration can be performed.
If you want to see this process in action, check out Jeremy’s video at http://edge.technet.com/Media/User-State-Migration-with-Windows-7/.
This same process works with ConfigMgr 2007 Beta 2 as well, again with the ZTIUserState estimate process automatically setting the right variables to perform a hard-link migration. (We are investigating some issues with this, so try it out in your lab to make sure you won’t run into these.)
There are lots of other features in USMT 4.0 as well. See http://technet.microsoft.com/en-us/library/dd560752(WS.10).aspx for the full list.