As mentioned already this morning, the plan with Ubuntu 13.10 is to have an experimental Unity 8 desktop powered by Mir for those wishing to toy around with Canonical's next-generation work. The default, however, will be Unity 7 in an X.Org environment. Even so, the Unity 7 desktop along with the Compiz window manager will receive some refinements for the next Ubuntu release.
Discussed just now during the virtual Ubuntu Developer Summit were bug-fixes and enhancements for the desktop Unity version in Ubuntu 13.10. Unity 7 improvements being planned for the October release include presenting new Unity indicators, more Unity scopes, the in-dash payments method, and selected design bugs will be addressed.
With Unity 8 around the corner, Canonical will not be investing heavily into Unity 7 improvements but rather taking care of selected items as a stop-gap measure until Unity 8 over Mir is ready for Linux desktop systems.
As far as Compiz goes, the Compiz 0.9.10 code-base will be used. The hope is that some of the earlier performance improvement patches will be merged in time for enhancing the Compiz compositing window manager performance one last time. However, with Mir/Unity-Next doing away with Compiz, it looks like the project will never reach version 1.0.