I am using both a stepper and servos on my mill, all with a single loop via magnetic scales. All of the velocity feedback that is required comes from the magnetic scales, there is no need for an encoder on the motor unless the servo drive requires it. There is no under or over shoot, it goes where it is told to go and is accurate to within plus/minus 1 pulse. In my case, 1 pulse is 0.000039 inches (1 micron).
it's good to see more programmers showing interested in hobby cnc and I hope they can get something to market in an affordable price range, I