So I've heard the G100 was overall a "failed" product... Google searches show even Mariss said it didn't do what it was intended to do and bemoaned the whole project.

However, I'm not sure what the specific problem was.
Was the firmware on the G100 itself buggy, or the hardware on it not up to the computing task?

Was the protocol flawed?

I saw complaints that it was the Mach3 plugin itself that was buggy- given the closed-source nature of Mach3 and it seems like only Art really knows how it works, I can see that as being a problem.

Was it supported for EMC2, or just Mach3?