I haven't used this cutting mat yet but I will let you know what I think of it when I do.
If I am teaching I can't take my guillotine with me as it is too heavy so I take this ruler. See the orange centre? That is the push bar that has a rubber base underneath it so that your project won't slip. It has a metal side and an acrylic side with centre find feature. The metal side is in inches and the acrylic side is in centimetres which I find handy if I am following an American template.
This intriguing tool allows you to cut a perfect square or rectangle of any size as long as you start with one straight edge. Fantastic if you are using up scraps of cardstock for stamped images to put on your cards.
Watch for the product review in a webisode in store.