Hmm.. lets see:
The most important things:
PowerPC support X
68K emulation X
Native MUI X
Other good stuff:
Threads X
Better handling of crashed apps X
Clean DOS X
ELF (not actually mentioned) X
amiga.lib integrated X
Other stuff:
AREXX - not native ?
Reaction - The 3.9 version looks like a mess..
Printing - ?
Misc sniffsnuff here and there I dont care THAT
much about unless its bugfixes or speedups.
Now how about manuals.. printed ??