I use the open-toe foot for piecing, because you really can see what you're doing. I use an edge-stitching foot for stitch-in-the-ditch. Pfaff machines don't need a 'walking' foot - the even-feed is built in. That's why I bought my first Pfaff. It works with almost every foot, and you can do fancy stitches as wide as your machine stitches, which a walking foot doesn't do. When I had a different sewing machine that required a walking foot, I hated the walking foot, too!
JoanneS