Radiator aftermarket

I don't know why everyone wants an aluminum radiator. The experience I've had with aluminum rads are that they are weak, and don't cool as well as a brass/copper rad. The upside of light weight I get, but unless it's a race car, I don't want to give up the durability and cooling of brass/copper.
I'm finding it cheaper to go aluminum..and will keep old one if I save enough I'll record it and have as backup .