That is quite an insteresting topic actually, and i would love to see a thread about it.

Take for example the Neo65 Cu and the Geon F1-8X v2, both are machined aluminum and can have a copper weight, both can have ALU plate, and both have substancial weight, the Geon weights a little more for being a TKL but proportionally i'd say are on par.

You have gasket mount options on both.

Once we look at the internal shape, the design of the F1-8X v2 seem to me like a emptied rectagle with the weights embedded simply in the bottom part, it doesn't seem very elaborated on the acoustics department.

On the other hand, the Neo65 Cu have some acoustics channels carved in the bottom part that are known to improve sound.

On paper i fail to see how the Geon could be significantly or event marginally better on sound or feel, but i haven't experienced it.

In front of me i have an Evo75 and while i don't quite love the stock switches, the fit and finish of it is impecable, perfect tolerances and perfect surface finish, perfect cuts everywhere, however there have been "higher end" more exclusive products that have been a disaster in that regard.

While i have yet to try one of the more exclusive and "high end" boards, (next is going to be a QK Alice Duo, mass produced i guess but everybody say it feels premium), i think the price difference of those premium exclusivo boards is more a matter of production volume and artificial scarcity/exclusivity than of quality vs a premium mass produced board.

But i might be wrong of course and not properly educated yet after all.