I don't know anything about the Sew Steady but I bought a Safco Folding Computer Table from Overstock.com for less than $100 ($2.95 s&h) and I love it! My machine sits on the adjustable keyboard section and my quilts are supported by the table. It was mentioned here at the board this summer and also by quilter Harriet Hargraves.
I hope you like whatever you decide on.