I bought one many years ago (not cheap, it was $600) and it was the biggest waste of money for me. It a Simplicity brand and has been nothing but trouble since day one. No matter what way I try for threading, I can never get it working right after changing threads. I've had it serviced a few times and it will work for a short time, then same thing if I change colors. I think there is too much slack in the thread and the thread picks up the wrong way underneath. I'm going to bring it to my guy and trade it for partial payment on service to my featherweight.
When it did work, it was great for curtains and such. If I were ever to consider another, I would get a self threading one...but it's not even on my wish list anymore.