I have an aluminum heater core. That sum' beech gets HOT. Many (all?) cars are sold new with aluminum heater cores, they heat just fine and usually better than our old cars ever did.
This is difficult to compare because of design differences in the two cores, and even the thickness of the metals. I have a different opinion about my Dakota. The aluminum core in the one I changed was VERY thin, and the the one in the current truck has plugged. They have incredibly small core passages.
