It looks like there will be two levels to aim for.
(1) ~10 MIPS or ~50MHz 68030 performance - FPGAArcade.
(2) Really quite fast 133MHz N68050.
There's a chance that both boards will include a chunky mode as an extension to AGA - Natami certainly will. If so, we could finally get a bunch of older 3D games running nicely without needing graphics cards.
Most important is that it could get more people programming the Amiga. Certainly it could become a nice hardware platform for the demo scene to target.
