Extremephono, I'm using Von Schweikert VR4 Gen III SE loudspeakers, a First Sound Presence Deluxe II preamp, a Hydra 4 conditioner with VH Audio AirSine power cord, dedicated 20 amp outlet, and an APL Denon 3910 universal player. I demoed the Nuforce Ref 8 throught the First Sound and direct from the APL Denon 3910 which has a volume control. I ran the Nuforce amps for 20+ hours until I had to return them. They were a dealer's personal demo units, and have been burned in for substantially more hours than the 50 you mention in your post.
As I wrote, I love much of what the Nuforce amps do. The fact that I do not prefer them over my VAC Phi 110/110 is a matter of personal preference, and I will not defend my personal preferences ad infinitum in these threads. I invite and encourage folks to buy-and-try the Nuforce Ref 8 amps for themselves.