Four blades.

Three blades usually cut a triangle figured hole.

Four blades usually cut a Square Hole.... Take a 1" triangle and a 1" square...... the square will have a greater area.... if you measure the greatest width of the triangle and even just across the square .... not diagonally but 90 degrees to any side. Edit: To my knowledge, most if not all three blade heads will cut an equilateral triangle... meaning that all the sides are equal. Quite often, you may not get a "hole" per sea, but a nice Mercedes Benz style cut....but with a square, you usually get a HOLE! And a hole in the dam lets out more water than a crack in the dam.

Flight characteristics are similar in my experience.... if you bow is tuned, it will shoot them.... if your bow will shoot muzzys well... then it should shoot dang near anything well. Muzzy are typically picky about flight, and require everything to be just so.