I actually think if all things being equal and a copper radiator is taken care of, it will last longer. Aluminum, no matter what, just gets eaten away over time by minerals and other crap in your cooling system. Copper is much better at holding up to years of having coolant in them. Even a poorly taken care of copper radiator can be flushed and can be put back into service even if it needs some solder repair. I wouldn't bother touching an aluminum one that has been damaged or been sitting with coolant for an extended period of time neglected. That's why they just replace aluminum and repair copper. By the way, in how many repair shops do you see old copper radiators sitting around compared to how many old aluminum radiators you see sitting around? That's because the aluminum ones all go to the recycler.