I just tried a little experiment yesterday. I've been using the supreme slider since I started learning FMQ. I've mainly followed Leah Day's ideas and like her approach. Yesterday I was almost finished with the quilting on a new quilt and ran out of bobbin thread. And I have to remove everything to reach the bobbin on my Pfaff. Decided to try not using the slider for the last bit and I could tell quite a difference. The stitches were more jerky and moving for the curves was more difficult, so I'll be staying with my slider. I do need to remember to wash it though as I do have to tape it down now. Don't think I did when it was new. As for leaving feed dogs up, my Pfaff will not do free motion until feed dogs are down.