The minimig is a great idea, but it isn't a step ahead. You can get similar performance on classical hardware for the same price.
The Clone-A seems to be targeted to a broader audience, which again means the focus on the Amiga is slightly less. So not knowing what that one brings, I'll skip on that for the time being.
The FPGA Arcade doesn't seem to bring the amiga forward in any sense, I've seen the 060 daughter board but still. that doesn't fix the slight incompatibility the 060 has.
The NatAmi however brings the Amiga forward, with their own core that is as compatible as it can be but has the speed as well would give the classic software a real boost with the new hardware. And since it's also enhanced with the SuperAga and 3d core, plus 512MB of ram, it also opens up for new possibilities which the others don't.
I vote for NatAmi.
