/this\
I have seen so many leaky aluminum radiators come thru the shop on customers rigs that I flat out would not install one if a customer brought one to me.
At one time, would have fully agreed, now only use copper radiators on full restorations. Aluminum radiators have improved in construction and its becoming more difficult to find conventional antifreeze to protect the copper ones.
And @Landpimp is right too. Current cost of a recore here is much more than OEM. But if you need a real high efficiency core, you gotta pay. Ask
@Vintij74 about the difference.
A properly designed aluminum radiator can easily be significantly more efficient than copper. Almost all commonly available antifreeze is biased to protecting aluminum, because no cars have come with brass or solder in them for a few decades.
Copper is more easily repaired, but it's a dying art, because no one except collector car owners have it done. We recently lost our last trusted shop, between the EPA pressures/expenses and low demand, he closed and retired. One of the repair challenges with the early radiators is the mixed metals, steel, brass and copper. The ideal repair for each differs, but they have to be stuck together, so compromise, often ends with side brackets coming loose from the tanks, etc.
The reality; new aluminum radiators are often a fraction of the price of having a copper repaired or replaced, basically disposable. Due to the available antifreeze, copper radiators are not likely to see the life that they did in the past and has improved the life of aluminum. A lighter, smaller, cheaper aluminum radiator, will often out perform a copper one. Other than a full classic restoration, or emotional/nostalgic reasons, don't see the point of copper.