XLR & Spades: Which is best? Pure copper, plated gold, plated rhodium or ?

For me base material matters the most, then coating mix.

I always find that pure copper as base material and silver/rhodium plating as coating works great.

What is best, depends on your system, whether you want to push things, mellow or refine.

Gold is the standard due to it's resistance to oxidation.

My preference is for silver plated copper - it provides better transmisson/clarity and faster dynamics

The tarnish does not bother me because

1. it only appears on the visible parts of the connector that is not forming the actual connection
2. reseating will re-establish a perfect connection
3. I do not clean my connectors because it makes no difference to the operaton or sound
4. 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