What is the difference between a Masticating and a Centrifugal juicer?

Centrifugal juicers are more commonplace, and in general, more affordable. They typically have an upright design in which food is pushed into a rapidly spinning mesh chamber with sharp teeth on its floor. The teeth shred the food into a pulp, and the centrifugal motion pulls the juice out of the pulp and through the mesh filter, where it is funneled out of the juicer via a spigot. In most centrifugal juicers, the pulp, once most of the juice has been pulled out, is ejected into a separate collection chamber. Centrifugal juicers work best with soft and hard fruits and vegetables, but not quite as well with leafy greens like kale or spinach, or with wheatgrass. 

 Masticating juicers, meanwhile, typically have a horizontal design in which a tube containing the auger extends out of the motorized base. Pieces of fruits and vegetables are pushed into the top of the tube, and they are crushed and squeezed by the auger. Juice drains out of the underside of the tube, while the pulp is squeezed out at the end of the tube. Because of the slower crushing and squeezing action, masticating juicers can process leafy greens and wheatgrass, and the juice that they produce will last much longer than juice made in a centrifugal juicer, which should be consumed right away as it starts losing nutrients nearly immediately.