When "Mrs. Santa Claus" gave me permission to buy my new machine at the International Quilt Festival last year, I was over the moon for several weeks. My first purchase after that was a 1/4" foot. Mine is wider at the back so the feed dogs make contact with the fabric, but it tapers toward the front so that the seam comes out perfect -- perfect being a relative term, though, since I am often in so much of a hurry that it is "approximately" a 1/4" seam. Ha!
The foot is a metal one and allows only a straight stitch, but that it what it is for anyway. No more having to tape a piece of paper to the machine bed!!