The automatic printing and experimental GNOME Shell support are neat in themselves, but what about "open" 3D drivers? If you've ever had to download Nvidia's proprietary drivers for a Linux system, you've felt the compromise — your hardware is recognised and utilised, but your operating system doesn't have real control over it. Setting up things like dual monitors is a true headache with proprietary drivers, so the more natively supported video hardware available for Linux, the better its chances at becoming a really usable workspace.
Fedora 13 is a free download, and should work on most Intel and PowerPC-based systems. Read the release notes for an overview of the new stuff, and Fedora fans (and newcomers) are encouraged to share tips and favourite features in the comments.