I don't know anything about any of the ECU rebuilders, but I would not buy one that was not in an original case. I would also want it to have the original number on it - like 6477 or whatever is appropriate.

You can read any stored codes with an analog ohmmeter and there is a flatline code for a bad ECU. I would at least want to do that before saying the ECU is dead.

Since some of the other ECUs almost made it run, the problem could be with the replacement ECUs, or with the components I mentioned that work with the ECU to create spark at the proper time - and it's not very difficult to perform basic tests with a multi-meter on a coil, a power transistor, an IAC stepper motor or a distributor. What if one of those components is bad and fried the ECU? At worst you'll fry the new one - but best case is you might not need a new ECU, or you might save the cost of buying more than one replacement.

Frank