I saved up for the ridiculously expensive Bernina attachment and went back to the dealer a couple of times for hands-on instruction but I have never been able to get it to work once I get home. The strips that feed into it have to be cut absolutely perfectly and it can't handle the bulk of a sandwiched quilt. I believe there is a very steep learning curve with it and keep vowing to sit down and practice with it until I get it to work but it's been a complete disappointment and a total waste of $$$ for me. I can't even begin to imagine how to make mitered corners with it.