Some people claim that inductive loads work better than purely resistive soaks.
There is the Tom Sholtz Power Soak, I think it was called, and the Marshall Power Brake, and the THD Hot Plate. They all work and everyone should have one. But the more you attenuate, the worse the tone. Power tubes and speakers don't really like inductive loads. Thus, a speaker isolation cabinet can get better tone at headphone levels than an attenuator set to very heavy attenuation.