There are 3 types of juicers: centrifugal, masticating, and The Norwalk (cutter/hydraulic press).
Centrifugal juicers, such as the Breville, Jack LaLanne, Hamilton-Beach, and Juiceman, partially shred and spin to yield some juice. Tremendous oxidation occurs during this process leaving many nutrients behind. Due to the size of the feed tube and design of centrifugal juicers, additional preparation in cutting of the produce is required.
Masticating juicers such as the Hurom, Omega, and Champion, use an auger to chew the produce to extract the juice from the pulp. This process is detrimental to the nutritional value and flavor of the juice, because the pulp is in contact with the auger far too long, making the juice over-processed and leaving particulates in the juice. Due to the size of the feed tube and design of masticating juicers, additional preparation in cutting of the produce is required.
The Norwalk Juicer is actually a combination of two machines sharing the same body and powered by the same motor. A Vortex Cutter for complete cutting and a Hydraulic Press which extracts the nutrients from the pulp provided by the Cutter. This method allows produce to have very limited contact with the Cutter, ensuring full nutritional value when pressed in the Hydraulic Press. After pressing, there is no pulp left in the juice and no juice left in the pulp.
This also allows for maximum keeping qualities. The Norwalk will accommodate produce up to 2 inches in diameter, limiting lost time in food preparation.