OK, I'll clear up some stuff here.
Cheese Whiz is a heavily processed cheese food product that has a very salty, tangy taste to it. It's NOT Velveeta or American Singles. It's used to top veggies, mostly, but can be used as a nacho sauce, although a bad one, IMO. It's thick and goopy and melts very easily and is very runny once melted. It's not real cheese, because of the TANG flavor of this product.
Velveeta is another processed cheese food product, that has a sharper cheddar cheese-like taste to it. It comes in a soft but solid brick form that doesn't need to be refrigerated before opening. It melts smooth, but remains a thick, gooey form which is perfect for nachos. It's very salty, but has a better, less processed taste than Cheese Whiz. It also comes in Singles form.
American Singles is a slightly less processed cheese food product that needs to be refrigerated. It is cheese, but still is processed. It has a light, cheddar and very creamy cheese taste, and doesn't taste as salty as the other mentioned cheeses. It doesn't melt as well as Velveeta, because it's more of a real cheese, but still melts well. It just doesn't flow well once melted. These things taste great, and I still enjoy them and so do my kids. Perfect for grilled cheese sandwiches or quesadillas.
Easy Cheese is Cheese Whiz in a spray can that NEVER needs to refrigerated, even after opening. It is the most processed cheese food product known to man. Not only do people use on crackers, but the military used it in bombs and grenades during WWII. Honest. Very light, to heavy cheddar taste, that depends on what flavor you buy, and is not as salty as the others. Doesn't really taste or feel like real cheese once in your mouth , but it works.