The copper-brass radiators and aluminum are very comparable performers thermally. Their respective thermal conductivities are pretty close although aluminum does have a 2x better specific heat capacity; but this is not that important in radiator design which is a conduction-convection system.

The copper-brass units are much easier to work on in the field and re-core. They tend to weigh more than the aluminum radiators. I believe that in general they are not as pretty but they are more robust than the aluminum units ........

My AFCO Aluminum unit for the '32 is polished and gorgeous! And it's out in the open where people can see it ...........

Kitz