Just spun up a Fedora 18 Gnome Live Beta CD inside Virtualbox 4.2.6 and Gnome Shell continues on it's path to almost total seemless integration.

The nautlilus file manager seems to have been replaced by "Files" File manager which has a very nice icon theme.

I'm noticing the 3.6.x LibreOffice seems to launch a lot faster.

I noticed F18 has NIC bonding available http://fedoraproject.org/wiki/Features/TeamDriver which on a server will be a great way of not wasting the typically 4 ethernet ports you get.

Final release for Fedora 18 is very soon: 2013-01-08