How do ferrite and powdered iron compare for use in an inductor core?

Ferrite materials typically have a much higher initial permeability than powdered iron. Because inductance increases proportionally to the permeability of the core material, a high-permeability ferrite core achieves a target inductance with significantly fewer wire turns than a powdered iron core of the same size. Distractors targeting temperature stability are incorrect because powdered iron actually exhibits better temperature stability than ferrite. Claiming ferrite has lower initial permeability is also exactly the opposite of reality.