I just recently purchased the Curve Master pressure foot to do a drunkards path and found it so simple to use. I took it to my quilt club to demo and they were all amazed at how quick and easy the curves come together without having to match anything. The curves sewed together perfectly.
I think for a new quilter such as myself, it completely took away my fear of curve piecing. For a more experienced quilter, I don't think they'd have a need for it.