How many kinds blades are there for electric pencil sharpeners?

There are two types of blades for electric pencil sharpeners: 1 high carbon steel 2, stainless steel These two blades are all on the assembly line.Production very fast And cheap. But we created a third electric pencil sharpener blade: 1000 times durable blades We developed this blade for half a year, which was manually polished; but the durable blade has high labor costs and long life time. This durable blade's electric pencil sharpener is equivalent to an electric pencil sharpener with 10 ordinary blades. Which one would you choose?