I have it with my Pfaff. I can't imagine piecing without it.

I like having that metal guide to stop me from going too far. I can still mess up (and I DO all the time) as the fabric can slip down below it.

I have the Pfaff 1/4" foot with a flange [guide] I use on my machine. I love it.

I found on some of the generic products there is a wobbling so the foot isn't really effective. I had bought a 1/4" foot with flange for my FW and it was so wobbly it wasn't useable. Of course I returned it.

I have quarter inch feet both with and without a guide for my Bernina. I hate the one with the guide, absolutely hate it. Fabric slips underneath the guide unseen or too far under the foot unnoticed until it's too late. It's so much easier to watch the edge of the fabric as it approaches and goes under any foot without having a guide on it to block that view.

That said, I mostly use the open toe embroidery foot (20) with the needle one click to the right. It gives me a perfect scant quarter inch seam allowance every time...with no edge guide.

I have one with a guide and love it. You may still need to adjust your needle position to the left or right to achieve your target seam allowance. Another thing. My girlfriend was complaining about how she hated hers. Come to find out, she was making HST by drawing a diagonal on a square of fabric and sewing a 1/4" on each side. This is not what this foot is for. The guide should almost touch your throat plate, and fabric should not be able to slide under it. When you need to sew HSTs, or any other seam where the raw edge of your fabric is not going to ride up against your guide, you need to use a different foot.

my patchwork foot has a guide. I love it.

The foot with the guide is intended for sewing long straight strips of fabric. It is not intended to piece blocks and go over other seams. I bought the foot with the guide for my grandkids but they do better with the straight 1/4" foot.

I have one and dislike it, so I never use it. Even if it were accurate (which it isn't), I would have to keep my eyes glued to the edge of the foot in order to get straight seams. I prefer instead to use an adhesive guide as a physical barrier against which I butt the edges of the fabric. This is much easier on the eyes, plus I can sew much faster and still have a straight seam. I have used moleskin for this, but currently this is my favorite:
http://www.amazon.com/Dritz-Quilting...dp/B0085L2Y2I/

I have one on my BabyLock Jane and a compensating foot on my Juki and they work for me. Not a scant 1/4" but, most of my quilts are okay with a consistent seams works for them.

I bought the 1/4" foot with a guide for my Bernina as soon as that foot came on the market. I love it! When I got a Featherweight, the first thing I did was order a 1/4" foot with a guide. That is the only foot I use on my Featherweight. Now, I do all my piecing in the Featherweight. With that presser foot, I get what I consider a perfect 1/4" seam.