I need to ask this question. I have heard the same type of person (thick rough beard) both say they prefer or need either 1) a wedge to really have the heft to plow down my thick beard or 2) I need the thinnest and sharpest grind I can get to be able to cut through my thick beard. What's the actual science of these things cutting through hair and how do you know which you need or could work for you? It seems they are both capable or plowing through the tough stuff or am I reading it wrong?