Windows 8 File History external hard drive backup passed a real world restore test on a client with a dead internal hard drive.  It kept backing up automatically until the failure and restored like a champ to the new drive.  I had thought ahead and added the Downloads folder to the Documents library (it doesn’t back up Downloads by default, which is a mistake) so the client had access to all the downloaded installation files to reinstall programs.  I like the fact that Windows 8 does not back up an image of the whole PC because the Windows 7 image backup program had rampant long term failures.  Perhaps the simpler Windows 8 backup will actually keep working.