I could not hear any difference with or without the cover. Las suela esta bien pero las correas de arriba muy apretadas al pie por eso no me gustó y plasticas horrible para el que no le guste las chancletas apretadas no se la recomiendo The only reason I had to replace it was the cable became frayed from where I had it pinched in-between a plastic retainer, so that wasnt really a failure of the mouse. But I?d say you definitely sacrifice some comfort for the look. In fact it?s so cheap I don?t plan to buy another pair of Vionic again. Fit snugly and dont fall out when you move. I have it now since October and the main problem with it is keep turning off( power off)I can not return it because of the timing expired,and wondering how I can reach out to them to adrees my issues. I dont know why Sony got rid of a good thing and left me with this sorry alternative. he LOVES these ! They dont work and randomly shut off.