As I wait for the next release of Fedora in 6 days, recently I have been spending some time away from GNU/Linux and playing with OpenSolaris UNIX. And might I add that it is a very impressive distribution. From the implementation of ZFS (and the Time Slider feature in GNOME) to Dtrace along with some other nice features.
I have worked with Solaris for many years and while Sun has always been ahead of its time with features and functionality, they always lacked in usability over the GUI. Usability over the CLI was always great and always there, it is just the GUI never looked good as it traditionally defaulted to CDE until recently (GNOME).
Spending more time with ZFS just makes me look forward to seeing a stable Btrfs in the Linux kernel.