Usually the difference is in the pumps. My personal opinion is that Cat pumps are the best. You also want to get a direct drive so you have no belts to deal with. Other than that, I dare say that most washers are basically the same. Look for the best warranty. Also, make sure that the machine has a "back loader" on it. This allows you to reduce the pressure on it so you don't take the pinstriping off your automobile. Be careful with these machines, they can cause alot of damage to self and property.