I am using it in my own practice and I feel it makes me get the ball started on line and rolling end over end.
I make myself make 10 five footers in a row daily with it.
I understand Mr. Phil Mickelson is using it as well.
Sorting Through the Circuit Player's Handbook.
B-Ray
I have been using one since late last fall. By far one of the best puting aids I have ever tried. It has really helpde me from inside 10 feet. If I could just stop hitting the marble on the left!!!