I called the Bernina dealer because I was curious. Iceblossom, you are right about the bobbins. 820 do not fit the 500 series but the 500 series bobbin is very large too. And these bobbins are not the same as a longarm bobbin even though they look about the same size. QuiltE, the feet and BSR are compatible and the 500 series has the knee lift. I was just in the dealer yesterday looking at the 570 QE.