My experience was similar to above -- horrible to install (like physically too long to fit the position of most wall sockets re. the floor) and confusing to set up.
Once apparently working, very slow and interference on audio equipment and radios.
In your case, I've also heard that if you can get a pair running successfully there are often problems adding extra outlets. Probably is house wiring but it may be inherent to the technology.
This is one of those ideas that sounds cool and works in the laboratory but needs much more development before it's widely applicable in the real world.