I am converting a Bridgeport Series II Interact 2 CNC mill to EMC.

I am currently using Advanced Motion 30A8T drives for all axes.

The drives give me a selection of tachometer mode (with feedback from motor's tachometer) or voltage mode (which means output the asked voltage without any regard for motor feedback).

The question is what mode to use. Voltage mode seems to be safer, in that if a tachometer breaks or stops sending signals, it would not go into a runaway mode.

Am I losing anything such as accuracy, by not using tachometer feedback?