Pretty much all I use. They don't hold water, scent, burrs, etc. Properly installed (tied on around the string), they are tuneable, and as mentioned that can make a huge difference in how well they work. In the right spot, it only takes a small amount. One mistake I've seen in leaving them way too long, which adds some noise. With all the different colors they can be made to match the string.
I like the look of fur, but I'll use what works best. For me, that's cat whiskers. SVL has made a fortune (literally) on rubber silencing equipment.