Ok Macwise, what is to be considered Open Firmware Hardware?
Not ours.
The OpenFirmware Macs are basically the same ones as are supported by OSX. There might be a few extras in there, as well, but that's the general list of it.
Personally, I have a 7200 that for some strange reason I haven't deposited in a dumpster yet, and I'd vote IT worst Mac ever. It DOES have PCI slots, yet they seem to be hardware flawed, and not actually usable under any OS. From the dark days of Apple, for sure.