This article evaluates the finishing performance of ultrasonic-assisted double-disk magnetic abrasive finishing process on two paramagnetic materials (copper alloy and stainless steel) with different mechanical properties such as flow stress, hardness, shear modulus, and so on. The finishing experiments were performed based on response surface methodology. The results obtained after finishing have been analyzed to determine the effect of different process parameters such as working gap, rotational speed, and pulse-on time of ultrasonic vibration for both work materials and to study various interaction effects that may significantly affect the finishing performance by the process. The outcome of analysis for the two different work materials has been critically compared to understand the effect of the considered process parameters on the finishing performance of the process based on mechanical properties of the workpiece such as hardness. Furthermore, the scanning electron microscopy and atomic force microscopy were carried on the workpiece surface to understand the possible mechanism of material removal and the surface morphology produced after the finishing process.