I am using Shunyata's ZR1 outlets and had lots of problems installing the 3 of them that powers my system. One of the outlets I replaced had the old type knob and tube wiring and the wires were so brittle I had to replace the wire to the panel and because the walls in my living room are horsehair, I had to also replace the box with an "old workbox" which I finally found. It was a nightmare.
I honestly can't imagine the new receptacles are a very dramatic improvement, but I could be wrong. I would love to hear from someone who had the ZR1 and am replacing them with the new ones.