I've had comparable Hills all yew; yew with boo core and all bamboo. I also have a custom Hill with yew out and boo and cocabolo in. To that you can add an all yew that I built with JD Berry's help that is a very wide limbed flat bow. Conclusion... the more yew the better. After shooting more than 40 Hills, if the boo is faster, as claimed, I never especially noticed it from a hand release. The performance seems to come from the deep core design, and if bows are similar in that respect, of comparable weight and draw, and the limbs are tillered similarly, they seem to perform well. I'd give an edge to the yew on smoothness. I've recently built three bows of all osage and I'd say it's just about like yew... another very impressive and beautiful bow wood.