Upgrading from the original 2 row, I purposely bought a copper 4 row just so it would 'look' original to the casual observer, as the aluminum (had to 'say' it as I spelt it) definately do not look factory. 'Most' go aluminum because their original (likely a 2 row) was damaged, missing, or just plain didn't trust its cooling capabilities, and as you found they are less expensive. As for cooling properties...yes, by design aluminum radiators disipate heat quicker. Will you notice a difference on your car's temp gauge?... 1. only if you are currently having a problem, and 2. Only by comparing similar sized radiators...in other words, comaring a 2 core copper to a 3 core aluminum is not a fare comparrison to see how much better the cooling properties of the metals are.
Unless you are after a more 'race car' look under your hood, I couldn't imagine spending the cash on something you already have in hand.
Except for safety issues, in car-crafting the owner's preference trumps any opinions or 'made-up' rules... With that said, do what makes you happy.