I dug out my 500 again today. I put on the original darning foot and had to mess with it for about 20 mins before it FMQ'ed adequately. I put the pressure to 0(D ) and my tension had to be cranked to 6. The only way I could get a decent stitch was to keep the feed dog plate at normal sewing height, and not raised. This means the feed dogs are up which is no big deal. So, I will revise my opinion from it FMQS terribly to it's o.k.... Still not my favorite in stitch quality and the ease of quilting, but it wasn't as horrible as I remembered. For some reason I think my 500 does a better job than my 401, which really doesn't make sense but there you go.