It seems like Ubuntu dropped Gnome shell and replaced it with Unity. Oneiric Ocelot will be shipped with Unity as default. But they say it will be much more improved.
Also heard a rumor that Fedora 16 will be shipped with unity.
Oneiric Ocelot will be powered using Linux Kernel 3.0 final
Other changes are improved application switcher, smoother compiz grid plugin and software center also got some improvements.