What’s the difference? Some sources of info I found interesting are listed below, each is a relatively long read. I understand the Jamieson and Smith’s, but there is only one picture comparison that I really get there, the one with the fair isle motives; I cannot detect much difference (in fact, any difference) in the comparison between the lace samples.
I list the link in the order in which I think they work best (from fibre to yarn).
Sue Blacker (Blacker Yarns) on Woollen vs Worsted