ok ... so here go another comparison between the Koss Portpros and the sennheiser 100 's ? I be not go to bear you . . both headphone be outstanding performer with a ipod ... I own they both ... so which one be my preference ? the sennheiser , for one reason only ... people use they ipod in mall and on the go . there be time when I want to remove the phone from my ear for a few moment -lrb- say , in a store or when have conversation -rrb- . with the Sennheisers , I can remove the phone from my ear and let they `` hang '' around my neck in comfort ... try this with the Koss 's and they will place a stranglehold on you . for this reason alone , I recommend the Senn 's . both , in my humble opinion , sound equally good .