I heard the same thing about the Power Brake, although it seemed weird to me that Marshall would sell a product that it knew to be destructive to its other products. On the other hand, the THD got sterling reviews, so much so that I bought two, one for my 16 ohm cab at home and another for the 8 ohm cab I was using at work. In five years I've retubed once and replaced three fuses. Sounds like normal wear and tear to me, but I would like to know why the fuses blow every so often.