I bought a small figure 9 last summer, just to play with. I am not very impressed. It does not grip the cord reliably. It could be that I'm using the wrong size cord, or one with the wrong compressibility or sheath.
I also have a good repertoire of knots, so I'm not highly motivated to find alternatives.
While browsing a used bookstore, I came across a new knot (for me), the Tricorn loop by G Budworth.
The relevant page is available on Google books preview
http://books.google.com/books?id=di...=X&oi=book_result&resnum=2&ct=result#PPA32,M1