After reading this paragraph from the Stereophile review of the Richard Gray Power Stations, it's not hard to see why you never see them advertised in the magazine.
Audio Line Source lobbied hard for a review. Here it is....
The Richard Gray's Power Company 400S manifested the same voice or coloration no matter how I used it. It sounded like your windshield looks after a big rig blows by in a rainstorm: The first swash of the blades cleans things up, but the view remains rather obscured. Unfortunately, sweep after sweep, the view remained the same, as through the window of an old, abused New York taxi. Another analogy: Drop your forearm into a sandbox and sweep it broadly across the surface. That's what the 400S sounded like.