This is why I went with Puritan Audio Labs groundmaster:
....To meet emissions regulations these appliances use their Earth connection as a dumping place for the interference they generate. And with substations often serving hundreds of houses, your HiFi Earth/Ground connection may well be connected to thousands of Earth Line polluting appliances.
Long before the problem of high frequency interference on the Earth Line became as serious as it is today, audiophiles in the know were utilising additional Ground Rods to provide an independent Earth to their HiFi installations. Elegant as this solution may seem, this is a colossally dangerous practice for the vast majority of current installations*. This is because it risks the potentially massive current from any fault between your HiFi and your local substation finding the easiest path to Earth through your HiFi with expensive, and possibly tragic, results! This is why the practice of introducing directly connected supplementary or dedicated HiFi Ground Rods is specifically prohibited by current UK Wiring Regulations. (Except in very specific circumstances). By utilising the Puritan Ground Master the hazards (and illegality) associated with the use of additional HiFi Ground Rods are totally avoided. And this is achieved without compromising the effective route to ground and hence the removal, of undesirable noise disturbance frequencies on the Earth Line. With the Puritan Ground Master used in conjunction with an additional Ground Rod the potentially dangerous route to Earth of mains frequency currents is safely isolated whilst offending noise and disturbance frequencies are permitted a highly efficient, extremely low impedance route to ground ensuring their elimination. * For the past 50 years houses have normally been connected using the Protective Multiple Earth (PME) system, whereby the Neutral Line is bonded to Earth at the substation and at other points along the way and with Neutral and Earth circuits separated at the point of entry to the building. This style of installation provides the greatest dangers if using additional ground rods without connecting though the Ground Master whilst other styles of household Earth connection will still benefit greatly with increased safety and performance.