Apple advertises their retina display with "you can't see any pixels". The S3 nearly has the same ppi (306 vs. 320), yet people complain about how they are somehow able to distinguish the subpixels? Something does not add up here.
You're not comparing the same pixels, one is a true pixel out of 3 subpixels, one is out of 2 subpixels. Thus higher subpixel density. You could see the colour difference.