I'm glad somebody did this comparison. It's good to see that the dual core CPU matched with 2 GB RAM is very comparable to the quad core Exynos international version. I guess the U.S. carriers were smart to ask/require 2 GB RAM to compensate for the dual core CPU.
I also think certain coding would need to be used to take full advantage of all 4 cores in the Exynos. I wonder how many programmers will write code specific for it.