If it's the one I'm thinking your talking about ... (see link below on Bonnie Hunter's page) I use it every day on my Janome 6600. I love the "lead in space" that it gives me, it's incredibly "visible" (unlike the little tiny piece of metal on the 1/4" feet), and mine is wide enough to cover behind the foot and a good deal of "lead in" in front of the foot.
My consistency in 1/4" seams has improved dramatically since I started using it.
They're not only for vintage machines - check your machine, chances are pretty good that even it's a modern machine it has a screw hole.
http://katiesquiltingcorner.com/2013...eam-guide.html