Upgraded to Fedora 17 "Beefy Miracle" in-place on the same image I've had since Redhat 6.2. It was a little more challenging than some upgrades due to moving everything into /usr, but overall it's working well.
And the origin of the name is pretty interesting, check it out:
Beefy Miracle comes to life here in Google+..
Paul Lindner , Jun 03 2012 on known.dev.inuus.com