The problem, of course, with micro-stepping, is that less torque is available from the motor, and this gets worse the more you divide up the step. For a stepper motor on any sort of machine that requires positional accuracy, this can be a bad thing. There are many factors that can easily overcome the holding ability of the motor which in turn will translate into missed steps, inconsistent positioning of the machine or just plain old stuttering and stalling. Even when the motor chosen is large enough to overcome the actual machine requirements, there's little accounting for the loads placed on it by the user. There are ways to help mitigate this effect, in the actual mechanical drive for the machine, like using ball or lead screws, rack and pinions for motion. For the most part, these motors are capable and do a reasonable job so long as the user doesn't place demands on it that are outwith the design parameters of the machine. Which is an art all in itself and really down to the operator's machining experience.
Personally, on all but the smallest of CNC machinery, I prefer using AC Servo's and drives, but that's a whole other can of worms
Personally, on all but the smallest of CNC machinery, I prefer using AC Servo's and drives, but that's a whole other can of worms