If using encoder feedback I would use servo's every time, BTW NEMA is not an indication of motor torque, that is just a mounting frame size, the torque can will depend on motor length etc, several torque sizes can exist for a given NEMA mounting, in both steppers and Servo's.
Also a common myth that servo's require gearing, servo motors like many motors have maximum torque at zero RPM.
I agree that for the same envelope size, steppers do have an edge over servo's, torque wise.
But servo's can be found with the same torque as steppers for a given NEMA mounting if searched for.
Al.