Some advantages of the SD40/SK1 combo over the SK1 vids are that all Sd40 styles and loops can be activated with the left hand of the SK1, with full Hammond or split Hammond and SD40 lead or layered voices With the touch of one button on the SK1. Some non organ voices on the SK1 are quite good, but not anywhere near the quality of the SD40. This is not mentioning the other features of the Ketron like vocal audio and midi uses.