Ah Patrice, you speak such wise words.
Connie and Izy, I have that foot, I bought it from my sewing machine shop. It is a Janome foot but fits my Pfaff Hobby machine (snap on feet).
I have only done one baby quilt with it so far, but I thought it was GREAT. I found that while stitching, you naturally have fabric on one side of the seam that is a little more prominent than the other side, if that makes sense? I found that if I made sure that the blade part of the foot was well in the ditch, and the side of the blade pushing against the more prominent side of fabric, the stitching was well and truly in the ditch, and never wandered (unless my mind did!).