HP or RPM. The earliest - and even now the cheapest juicers - are centrifugal machines which shred the produce and squeeze out the juice by spinning it in a perforated basket. They rely on high RPM - 10,000 and more. The higher the RPM the larger the pieces of fruit and vegetables the juicer can process without slowing down or stalling. However, we learned that high RPM creates heat and adds oxygen to the juice, both of which destroy many nutrients. High RPM machines are also the noisiest - sounding like airport runways! So today we have what are known as "slow" juicers which have very low RMP - as little as 80 - creating minimal heat, oxygenation, and nutrient loss. Horsepower (hp) should be at least one-third to one-half. Otherwise the juicer will have a difficult time juicing the hardest vegetables such as carrots.
Recommended Appliances. I highly suggest the latest evolution of juicers known as "slow" juicers - easy to clean, able to juice greens, and great nutrient delivery. There are several great manufacturers such as Hurom, Breville, and Omega. I use the Hurom but it now has an inferior warranty to the Omega and Breville. Go to Google and type "best juicers" for short and informative video advice about the different juicer brands. These reviews often involve very entertaining and informative comparisons.