I have tried it and I don't like it for the same reason I have trouble
with other two ply twisted threads (unless I am knotting between
beads), they tend to stretch out after you tie your knot and you end up
with a little thread showing around the clasp. It's not as bad that way
as silk but it still does it. I now only use mono filament like nymo or
crimps with soft flex or beadalon for heavier things.

I know some people can use these types of thread so maybe it's just me?

Ingrid
http://www.mermaidscove.com

I've heard about an alternative to silk cord called Stringth, but
nobody I know has worked with it. Have any of you used it?