I would buy a Sew Slip mat, instead - it's twice as big and it costs less than the Supreme Slider. Here's one on eBay, so you can see what it looks like:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=120606839114
It's sticky on the back so it stays put, but it's very slippery on top, so your quilt glides over it. I can tell a definite difference between using and not using the mat.
If your feed dogs don't lower, you can enlarge the hole in the mat to expose the whole area of the feed on the needle plate. If you don't, you will get lots of skipped stitches.
The back loses its grip if it gets dusty/linty, so you just rinse it under cold water and let it air dry and it's sticky again.