I live by the Japan Oak sticks. I won't use anything else... aside from the nylon tip issues that I spoke of earlier, I have never broken a Japan Oak stick.
Heck, I've even TRIED to break one of my old pairs because I had picked up 2 or 3 new pairs... I couldn't even do that! I gave them to one of my high school students and he managed to break them on a marching snare (although I suspect that he just sat there hacking away at the shoulder until it gave way). Did some serious denting to the marching snare's rim, though, FWIW.