Well, I do get to hear music live often enough to remember the sound in broad terms - while recording it, if not otherwise. The super exact memory of any specific violin, piano etc is rather short lived - general impression regarding say strings, woodwind, brass, kitchen department (percussion) etc - is not.
Floats are different beast than normal headphones; they are the original ear speaker in the true sense of the word. Although I do not doubt they can be measured, I doubt they can be measured with sufficient statistical accuracy or averaging of the (numerous) result(s). What is simply not understood well enough is the fact there are no pads to alter our natural hearing as with almost any other headphone ( most notable exception is AKG K 1000 ) .
So far, I have not seen a measurement that would produce a graph to show just how much do pads of a certain phones under test alter our hearing - that graph would be the most relevant to the perceived SQ if the transducer itself is assumed to be "perfect".
It is sad to see Michael from Germany doing such disfavor to a valid transducer with fervent claims of it being #1 Uber Alles, hype, etc, etc. No, I have not heard the new Jecklin QA - but they would trully have to mess things up pretty badly to take away the prime charm and allure of the Float - that is to say the reproduction of the acoustics music was recorded in. I have not have yet had the privilege to hear Stax 009 - yet I can say it can never be a match for Float regarding soundstage. And vice versa - Jecklin would never be able to match the bass from any Stax. They are different designs, totally different concept, only thing in common is electrostatic principle of operation. They can not be directly compared - certain type of music and recording techniques will favor one or another on sample to sample basis.
For the most important part of the frequency band we hear, the midrange, Float with its lack of earpads does have advantage over any padded headphone. It is not as sucessful at acoustically dissapearing as AKG K 1000 - one can hear Float when worn on head with no musical signal propadated through it - the enviroment does get changed from that of zero on your head. The difference between the old Precide produced Float and new QA version in this regard should be minimal, if any. Both will be worse than K 1000 and better than anything else.
Make or break in electrostatics is not the transducer itself ( it is very near perfection, at least in the midrange ) but "electrics". Precide produced transformers left much to be desired, to remain polite about it. Bass was particularly poor, the louder and lower the signal , the worse performance from transformer, compounding the already compromised bass performance of the transducer even further. Properly driven Float is no bass champ, but can hold its own well enough. Hope QA version of transformer is significantly better than what went on before. If I understand it correctly, they drive it with Quad 405, an amplifier that has, despite being around for ages, yet to gain full recognition by public at large. It has been designed to drive electrostatic speakers and smaller "ear Quads" are electrically very similar load. 405 is quite special if upgraded properly. Taken together, It can be a good start for QA.
Once you try Float for at least a weekend time, it should be clear comparing it to Stax or anything else is apples and oranges - only way to determine what suits you best is to listen by yourself. It is unique sound, not achievable by anything requiring pads. How much has QA improved upon Precide produced original remains to be seen/heard.
And yes, more often you do get to hear the sound live, more chances there are to embrace Float in the end.