well. i dont think amiga os can be concurrent to the mainstream options available out there, but availability of mainstream hardware to run "amiga os" might be an improvement to "amiga os users" themselves.
from my perspective which is actually pretty bound to the amiga and related hardware and having a limited experience with os4 and arosx86 everybody needs to find the solution that suits his interest most.
here i am slightly biased towards aros, especially aros68k as i suppose it offers opportunities at least in some areas, a fair trade of research in others while it still conserves the legacy where its important, that means in therms of open source code and binary compatibility.