I'm longarming a silk quilt right now. It's been taking a while but not because of the silk. It's raw silk which is thicker than some silks. The silk has been fine as far as stitching. It reacts like cotton when you remove stitches. A little rub with your thumb nail and the holes close up. It's been taking me a while because I'm having problems with small loops on the bottom which I think is a bent bobbin. But this has caused me a lot of stitch removal as I didn't catch it fast enough.
I've never quilted taffeta or satin but did make my daughter's wedding dress of satin many years ago. I was very afraid of creating a "run" in the fabric but that never happened. I think keeping a sharp needle in the machine helped.