Re: hardest rosewood?
Pau Ferro is one of my favorites. It's a little waxy feeling, and depending on what your body chemistry is, it can feel like it has a little "drag", but not for me. My hands are dry and I love it. Most people consider Ebony to be fast and smooth, but for those who have that same kind of body chemistry, Ebony's flat, non porous surface can also have more drag than Rosewood. I guess what I'm saying is that it's rare, and if you already like the feel of Ebony, you'll probably have excellent results from the Pau Ferro.