A walking foot is helpful for straight line quilting. The darning foot for free motion because you have more freedom over turning the quilt with the darning/hopping foot.
I find the walking foot to be extremely helpful. I finished one seam on a quilt, flipped it over and saw all the pleats and tucks and then looked more closely at my machine and realized that I still had the 1/4 inch foot on it.
Cheers, K
Cheers, K