I did buy the Sew Slip. Much like the Supreme Slider. I don't care for it because my quilt tended to pull the edge of the slider thingie up and so it caused more trouble than without it - My sewing machine bed is very slippery anyway and my acrylic extension table is flush with my sewing table except for about 1/4" so I have no trouble without a slider - the idea of using the silicon kitchen mat thing is genius! I just saw a very large roll of that at the Kitchen Outlet. On the other hand, lots of folks LOVE the Sliders.
Good luck whatever you decide.