My preference is for silver plated copper - it provides better transmisson/clarity and faster dynamics
The tarnish does not bother me because
- it only appears on the visible parts of the connector that is not forming the actual connection
- reseating will re-establish a perfect connection
- I do not clean my connectors because it makes no difference to the operaton or sound
- I do not use any type of jointng compound
I am happy with my sound and see no advantage in obsessing over tarnish, because most of the connctors seldon tarnish in the atmosphere of my home
I have tried other types of metals and platings and prefer dynamics and clarity of the silver plated Copper
Regards - Steve