The problem with cutting into panels with a standard hole saw is that they will drop through into the panel if you don't ease up on the pressure at the end of the cut. A hole cutter (any of the major brands ) have a shoulder that prevents this from happening. As for breaking teeth and pilots, that's what the washer is for. You drill the pilot thru the washer hole and when it drops through the cutter lands on the washer which spins and doesn't grab. Remove the washer and finish the hole. Much faster than all that mandrel and pilot bit swapping.
