I was wondering about this as well- I wanted to try out the new profile copy stuff from appsense.
We've been using USMT run from powershell with great success. In our case, we just want to pull a single user's profile from PC A and copy to PC B.
One script runs on the source system, queries AD for the computer's "managedby" attribute and calls scanstate.exe for the user (and points to customized XMLs on what we want to grab). Thus if we want to grab one user profile, we just go into AD and changed the computer object's managedBy attribute.
For the deploy/load side, we run a similar script that looks up the destination computer object's "managedby" attribute and runs loadstate for that user and the process is complete.
We use a server file share to store the profiles until we're happy with the migration and then we manually remove them. Requires user on source system to be logged off to get a clean profile copy scan.