I have been using my cup adaptor for about a month.  It is bulky and heavy.   The cup is tall and with the ginormous lid is poorly balanced and top heavy. Overall I'd say my ninja and bullet are exceedingly more convenient for smoothies and shakes. The adaptor portion takes up some space. That said however, I am trying to consolidate appliances and nothing compares to the awesome capabilities of the Vitamix blender so it wins out as the keeper.  But I'd say- get your engineers back to the drawing board.