Microstepping is a product of the stepper driver. Any problems with microstepping are going to just sit on top of that typical +/-5% step angle accuracy. Remember that the step angle inaccuracy is non-cumulative from step to step. See: http://pegasus.cc.ucf.edu/~cham/eas5407/project/Intro_stepper.pdf section 10. I guess that a microstep's holding torque will also depend on the rotors magnetic field strength. Problems with holding torque will look like a quantized and fully cumulative position error. It would accumulate over all layers of the print and not be cyclic.