I have 2 of her slotted mats and have no problem at all. You just have to use a rotary cutter straight up and down. You would use it that way with a regular ruler or else you won't get a perfect cut. They are meant to be used vertically, not at an angle. It shouldn't matter whether you are right or left handed. My olfa cutter lets you put the blade on either side of the cutter depending on whether you are a lefty or righty.