I have the big foot and really like it, but it is plastic and a closed foot. I do use my open foot metal one sometimes when I really need to be precise in what I'm doing. The reason I like my big foot is that it has a slight rounded base and moves over nearby pins and doesn't get caught on them - this gives me a little more flexibility in the area I can stitch in before moving my hands. The larger base of the big foot also helps keep bumps of fabric away from the needle when I'm not as careful as I should be and am trying to push the envelope.