Are new aluminum radiators better?

Aluminum is actually far better at thermal transfer than brass.

Brass vs. Aluminum: Radiator Thermal Properties

OP, run aluminum if you're not on the OE/Resto kick.
And a good sacrificial anode won't hurt, either.
Yeah I dont care about OEM on the engine. Only on the exterior since I use it for movie/tv. I just need cool and reliable.