On a recent quilt, I was using dark thread in the needle and light-colored thread in the bobbin. I was getting "backlash" on the backing of my quilt (tiny loops of dark thread) when changing directions in my quilting. Tried Bobbin Genies, and didn't notice any improvement. I tried all sorts of tension adjustments, and finally decided to live with the backlash.
P.S. I think I'll stay away from combination of light and dark threads for the time being! ....