Sisal v Synthetic Sisal

I really like the idea of layering rugs with a pretty rug on top of something much bigger and neutral like a sisal.  The only reason I didn't suggest it earlier is that I thought the reason for looking at smaller rugs was to allow more hardwood floor to show around the edges.  If we're okay covering the wood floors (which I am), then definitely, let's look at big neutralish rugs.

And I like sisal, but, I don't like real sisal because it doesn't feel so soft or good on my feets and I think sisal hates moisture (which is probably not a big issue).  But I do like synthetic sisal plenty.  Here are just a few quickly collected examples -- there are lots more out there.