This is going to be a weird response.
A few years ago, Jeff Bagley built a 'quasi' second order (balanced) 2-way. By all accounts, it was the best 2-way all in attendance had ever heard. After the fact, the naysayers started commenting 'you need appropriate drivers for the circuit'. Now I'm not the brightest bulb in the chandelier, but if it's the best 2-way to date, and you need the appropriate drivers, than choose the appropriate drivers?. Simple.
The fact remains, there will always be skeptics in every field.
Kijanki: your statement; 'sound is the only proof' holds true here. Those people in attendance called it the best. The question is: did he drive his balanced speakers with balanced amplification, or where they un-balanced?
Here's where I turn into a partial salesman.
I believe I've invented the first 'quasi' second order 4-way crossover. My speakers are driven by all Atma-Sphere Dual Differential amplification, and they will be unveiled at this years TAVES (Toronto Audio Video Entertainment Show). I put forth, since 99% of all speakers use parallel crossovers, and these are un-balanced, then dual differential circuits have never had a speaker which will highlight the difference (I wanted to say 'highlight their superiority', but that would have opened up a whole new set of insults. Being married, I already get enough of those)
The only industry person whose heard them is George Klissarov from eXasound. He called them magical. There was not enough time to get them to Axpona. They may be at The Newport show.
Since my website, and speakers, are still under construction, I'll leave it at that.
On my website "let your ears be the judge" is a common statement. In the end, "Sound is the only proof".
Time will tell if a)I'm delusional, or b)I've done it.
Sorry for partially highjacking a thread. Buy Dual Differential amplification. To my ears it is a lot better.