One recurring theme I keep hearing is that there is no “perfect” steel. It all depends on the intended use, balancing toughness and hardness, and how much you want to pay. But 5160 is very popular for swords and machetes because it’s tough and springy. A lot of makers use it.
That would be true in principle, but we are living in the age of designer metals so that may not be as true as it used to be when you were limited to finding the best possible steel.