We've been internally testing and playing this, and it looks like it's about 1 month away from release. We might try to sneak in a couple of new characters, and there is one issue with Linux involving shaders that is still unresolved, as well as menu mouse support in Linux, but for the most part, it's just about ready.

But this is some of the new stuff it will have -

8 new levels (25 total, we removed a couple of them, which we considered not up to par with the new content)
Deathball game mode. Similar to UT's Bombing Run.
Mutators (instagib, rocket arena, low grav, regeneration, vampire)
Improved Bot AI (too much to list)
Colored names (ripped straight outta Q3 )
Q3 style console (ditto)
Enhanced server browser
Enhanced menu and HUD
Alternate firing modes
Cleaned up an assload of either unused, or poorly written old code(i.e. particles). Runs even faster than ever before despite all the new features.

http://www.planetquake.com/cor/arena