This topic may be cover a little too wide a range of subject matter. I'm going to stick with aluminum vs Copper/brass for starters.
Also, one can have literally the opposite viewpoint on this and still be right! There are so many factors that contribute to cooling, there is no 'correct' answer.
From a scientific standpoint, Copper is better at dissipating heat than aluminum. The problem with copper is that it is too soft to make a radiator out of. So additional material is added to the copper to make Brass. Once this happens, Aluminum becomes better at dissipating heat than brass. Aluminum is also stronger than brass which seems impossible because it is so light and seems to dent easier.
Now you have to apply this to various design radiators and various material of radiators. This is where things get very complicated as vehicle specifications, price and functionality are added to the equation.
One thing to point out early on in this topic. Aluminum has been used by OEM mfg's in higher end vehicles for many many years. The reason they were not used in everything is mostly due to cost reasons. Historically aluminum has been much more expensive to harvest and to then fabricate. In the last 10-15 years, aluminum pricing has dropped significantly, robotic tig welding has become available and affordable and at the same time the price of copper (the main ingredient in a traditional OEM radiator) has gone up in price dramatically. Hence why literally ALL new car/truck radiators are now made of aluminum cores. The tanks are commonly plastic and epoxy'd on. This is done as a cost saving measure. Otherwise, the tanks would be aluminum as well.
Let the fun begin!