Yes, the OFE is the most different, but not “extreme”.
The cable DESIGN is 99% of what you hear. This is exactly WHY the affordable TPC copper can be used.
Me, personally, do not see ANY good technical reason why lower priced copper is either never offered, or in a less correct R, L and C design.
I use the exact same design so the TRUE merits of the copper is evident, or not, to you. Everyone gets the best DESIGN. The copper can’t hide it’s spots.
As far as connections, just remove as re assemble annually. Cleaners aren’t a problem at all if you have some, but it isn’t necessary as the connection is deeper than the surface, and self cleans when you reassemble the connection.
Spades usually have more contact surface and higher pressure than a banana. It is all about those two things. Simple, really. But, once you pass good enough it is simply bragging rights, I agree. We use top quality spades and banana, so good enough is achieved in the worst termination of you want to look at it that way.
I settled on the $$$ cable designs because they work, or why do this? The speaker cables give a really nice open sound that is really nice. Imaging is far better and precise than cables that don’t try to minimize wire coherence, but THAT is why the costs go up an up. 48 wires is a lot more than 2 in a zip cord.
Then you have to negate reactive elements with all those wires. Good coherence and low reactive variables fight each other. Doing one is easy, doing them all is what you pay more for, and it better be explainable to the customer and that’s what you really deserve to know and understand.
Measured electricals aren’t BS. We test every assembly. Wire coherence is easy, more and smaller wires offer better coherence per wire, but all those wires have to act like one wire, or it is worse than zip cord. 48 signals arriving at different times and with different reactive variables is a train wreck.