I sew on a HQ Sweet 16 sit down. To my left is a Horn Quilter's dream sewing table in which I usually keep the sewing machine part down. It comes with a cover to make a flat table when not using a machine in it. For a long time I used a standard card table and it worked perfect except it wasn't 'slippery'. So we found an Amish craftsman to make me a cabinet to fit the exact dimensions needed to fill the space I had available. Now my only problem is the front of the table with my quilt in my lap.
A HQ tutorial video quote always comes to mind when I am quilting. It is this: "Let your table do it's job! It's job is to hold the quilt". I often then turn my quilt so the table is holding the quilt, not my lap. We get on so much better then!
Good luck!