Resonance. Most OU devices use resonance in some aspect, and the tricky hard to replicate part is just that. Someone will remake something and use the wrong transistor or make it all out of wood instead of copper, or give it a funky waveform instead of what it needs. All the replications of OU or crazy-U devices I have seen have all not been to spec, and the ones built to spec usually worked. Like for example the joe cell's proportions are based on the golden ratio. I've seen people try to make tin foil abominations and call it joe. Or someone thinks they can make a Bedini wheel better then Bedini and then wonder why it wont even work now. its funny.
That, and the magnet gang is out there breaking inventor's toys and threatening their familys. So, its really up to the small guy to take some information, weed the disinformation out of it, and remake the device their own, and report back to the collective what they did and how.
One note with the tesla switch. You need to use very high frequencies to get the good stuff. 60 hz is way too slow. Thats why you need a really big SWITCH. optoisolators and transistors fail too often at those speeds, you need a reliable mechanical switch.
If your looking for overunity, a 1=2 situation, it wont happen (unless your part deity. Jesus had overunity fish at his sermon. So it is possible... ). Understand nature, learn about energy and matter. Learn about fluids. Electricity is a fluid. Contemplate the magnet and what it is. Then meditate and ask collective unconscious what IT thinks. Maybe you'll figure something out.
Maybe you don't need to find overunity. Maybe you don't need to use electricity for heat, use the sun! One man-sized fresnel lens (40$ ebay) can BURN concrete and MELT glass in SECONDS! Good luck getting the watts you need to do that with a circuit. You don't need to use washing machines and dryers for clothing, do em by hand! Take all your conveniences away and whats left? Just use what you have the way its supposed to be used. Garden of Eden style.
You will find "it" when you know what "it" is I suppose.