edit: i couldnt get adoom to run on my machine, it breaks up with the same memory allocation error on aros as under aos, so no timedemo for the time being, sorry.
ADoom uses gfx card as framebuffer (direct copy to gfx mem) so there will be hardly any difference because it doesn't rely much on the underlying OS, just like Quake.
If you forced me to choose between harakiri or using Wazp3D on a classic I would choose the former.