I have noticed that grounding boxes do not seem to get much attention on Audiogon and actually in the USA. Check out "What's Best" Forum they seem to get a lot of attention there.
I own a Silver Tellus Entreq box, and I have made a few DIY versions that I believe far exceed what the Entreq unit does.
The Tripoint is on my future list, but boy are they costly and they don't seem to be available used. Plus, I'm not sure if there is even a USA dealer.
ozzy