AROS is too strong today and I think Hyperion would find it hard to justify paying for x86 OS4 next to AROS today. Had it been done 2-3 years ago it would have been possible.
I have no ppc machines so i can only argue: perhaps aos4 is more stable than aros is?
I love aros but often i have to reboot it because it crashes (i7-p7p55-9800gtx2+ machine).
If aos is more stable than aros is i'd buy it today.