cecilia already gave pretty nice round up of AOS4 developments.
Other than that...
It's about as usable as traditional AOS (has some new stuff, lacks some other).
It is years ahead of AROS (which is years behind AOS3.9).
It has some things MOS1.4 does not have (TCP-IP, Altivec), It lacks some other things (WarpUP support).
Applications and SDL game ports appear daily/weekly.
Next public update release will deliver better support for PPC750GX CPU and perhaps some other fixes.
Next bigger update will be the final release, I think. (I predict that it will not appear before the end of the year)
