According to the sheet describing the feet, the Flip Flop glides around applique and gives you great visibility, and the Sneaker is for micro-stippling. Beyond that, I'm not sure what the real difference is, because they seem basically the same, except with the cut-out on one. I haven't tried the Sneaker yet, but I just put the Flip Flop on my machine today, since I wanted to "glide around applique," and it is AWESOME!!!! I was perfectly content with my original foot, even though I had to strain sometimes to see my stitching, but I love, love, LOVE this new foot!!! I don't know how I lived without it! I'd also be curious to know the difference in purpose between the two feet and the reasoning behind it.