MorphOS is the best Amiga OS ever made. The fastest, most modern, most compatible and best implemented. It would be nice to see it running on architectures other than PPC, but even so it leaves the other alternatives in it's dust.
I agree 100% about MorphOS now that I have used all three modern Amiga's. I still voted for AROS though because PPC is a dead end. It is that great that the PPC Mac ports have made it available for cheap for all that want to use it.