Wasn't the Scholz Power Soak the first marketed attenuator for guitar amps? Or if not, a very early one. It may have got a bad rep because it was an evolving technology, or something that people just didn't know how to use safely. :dunno:
I've read a few horror stories about the Marshall Power Brake having component failures/meltdown which in turn damaged the amp it was being used with. So I didn't buy one.
I bought a THD Hot Plate and have played lots of gigs with it with no problems. It's great for pushing a 50w amp but keeping the volume pub-friendly. I don't use it at bedroom volume. The only thing that frustrates me with it is that the attenuation is in big steps at higher volumes - 4dB, 8dB, 12dB, 16dB. From 16dB downwards it's fine-tunable. This can be tricky if you're gigging and want to up your volume slightly. Going from 8dB attenuation to 4dB attenuation is quite a big step.
I'm very tempted to try the Weber Mass as I believe it has finer control.