I just got it, and just started playing around with it. It came as a perk with my setup. I like the patterns that come with it, and look forward to trying them out. You can also graph yourself, but it's as simple as using Paint or something on your computer, with lines and curves and such.
It *does* allow you to size your pantograph or full-quilt. I've seen this listed betweeen $100-$150. Not sure if I'd pay THAT much for it. Perhaps when I fiddle with it more I would say yes I would...