So, everyone agrees that AmigaOS 4 have advantage here, over all the other AmigaOS alikes.
No, not really. It would appear that a significant portion of the posters believe MorphOS has significant advantages over AmigaOS4.
Frankly, since they're both very similar and MorphOS is more mature (and faster), I see no point in being argumentative.
AmigaOS is nice. Buy it if you have the funds for the hardware and the OS.
I'm sticking with MorphOS because of its obvious advantages and the fact that the investment needed in hardware and software is less.
And, in the long road, any company devoting the time to creating PPC based software is unlikely not to support both OS'.