I heard of it and then decided to try the technique, but being who I am (cheap) I made my own.
I used the techique in the background of my Nov wall hanging. I just wanted it to be a background and it worked extremely well for the look I wanted (recedes to the backgound, seams line up, corners match)
You can't tell from the photo but I machine qulted the whole thing with my domestic machine and had no problems.
Would I try it again? Probably for a wall hanging, it seemed a little heavy for a quilt, but that could be the interfacing I used. I REALLY liked using it for this project
(the wallhanging is square, the photo is not)