The easiest way for me to make fast, consistent, accurate 1/4" seams is to use an adhesive physical barrier, not a quarter-inch foot. I like these Dritz strips the best:
http://www.amazon.com/gp/product/B0085L2Y2I/ and have found them on the quilting notions wall at JoAnn's but, if they are not available, I cut my own strips out of mole skin (found in the foot section of any drugstore) and pile the moleskin two-high. When sewing, I simply butt the fabric up to the adhesive guide. I can sew very fast this way and still maintain accuracy. One of the reasons I think this method is superior to a quarter-inch foot with a guide is that the adhesive guide can extend a couple of inches in front of the presser foot (which helps a lot to keep the fabric lined up properly) and also can extend a little behind the foot.
Be sure you understand the "scant" quarter-inch that most of us use for piecing. Even the Dritz ruler (red ruler sold with the adhesive strips) that is supposed to be used to position the adhesive guide is wrong; I measured it, and it creates a full 1/4" seam (too big for quilters). A good way to test your seam is to sew three 2.5" strips together, iron, then measure. If the seams are an accurate scant 1/4", the width of the strips will measure exactly 6.5". If it measures less, the seam is too wide.