I can’t comment on the Juins, but I’ve been using Hy-Rds for about 2 years now, I think. I was a long term BB7 user before that. The Hy-Rds don’t need the regular adjustment the BB7s required to stop disc tinkling, and seem to have stood up to winter conditions better, which was the other problem I experienced with BB7s.
I think TRP have updated the design since the original model.I had a problem with one piston that wouldn’t retract fully, despite cleaning and bleeding. When I contacted TRP to ask for advice about how to fix the problem, they sent me a new set of brakes (front and back) although mine were out of warranty.
I found that there was far too much empty lever travel when I set mine up originally. I found an internet tip to fit the cable clamp on the underside of the actuator and clamp the cable on the inside of the bolt instead of the outside, and that made a huge improvement to the feel of the brakes.