SyncToy is one of the best utilities I've ever used. I'm using it to make backups of critical files (OneNote files, some source that's not in source control, work documents, SharpReader settings to read from multiple computers and stay in sync) from my hard drive to my USB thumb drive. I plug in the drive, start the app, click a button, and a half dozen folder pairs sync automatically. And if I modify some of those files on the thumb drive from a different computer, SyncToy is smart enough to move changes back the other direction. Well done.