I agree with Lacee.
I have,in-house, right this very minute, Synergistic Research Tesla Plex, Tesla Plex SE, Oyaide R1, PS Audio Power Port and Power Port Premier, FIM and FIM Gold, Maestro and the Furutech GTX-D (Gold, although I wanted Rhodium).
The Furutech is so far ahead of ANY of the others, there can be no disputing the differences. The grain is akin to that of the Hurricane amps, which is to say: Zero. The dynamic range soft to loud)and contrast (tiny inflections) surpasses the Synergistic - which I bought only 6 weeks ago. The Furutech has 16 hours on it so far.
The first 10 minutes, I couldn't tell. But 3 hours later, I could, and in a BIG way. Got up today and listened to it 20 minutes ago, with the amps not even warmed up, as I wanted to hear what it sounded like from a cold start, and whether or not the system being warmed up would hide what it sounded like last night with the system warmed up and 3 hours on it.
It was so obviously better, even cold, I just blinked and muttered, "Wow."
I've had audiophile ac receptacles since 2003, so I'm not new to this, just as I had tube traps back in 1988, dedicated lines in 1989. I've done EVERYthing that could be done to make it sound better (including something most people scoff at: keeping the speaker cable off the carpet, which I demonstrated made a difference back in 1995, at the publisher of Fi Magazine's home, with Dick Bel, Tom Miiler, Sally Reynold (TAS' former Executive Editor) and a few other VIPS). It works, and if you're not doing it - or you don't hear it, I don't know what's wrong with your ears. Every speaker cable I've had, which includes: Nordost Valhalla, Transparent Audio Ultra (from 1993), then the Transparent Reference, MIT, Shunyata Andromeda (Constellation Series)and a few more. How someone cannot hear the difference with interconnects and speaker cable off the carpet is beyond me. Enid Lumley knew what she was talking about. (People just lift it off the carpet without understanding their cable will take time to settle. Wait 4 hours and THEN listen to it.)
Back to the subject at hand: if I can determine a way to put the Furutech in my PS Audio Power Plant, it's going in there, too!
Unquestionably, THE BEST. BAR NONE.