TouchWiz: On the left, a Samsung phone, of some sort, running something; in the middle, an iPhone 3G/3GS running iPhone OS (as it would have been); on the right, a Samsung phone of some sort, running some sort of iPhone OS copy. No, you’re right, of COURSE it is different. Just look at how different it is! Look! Are you still looking?
(via The Verge, who seem to be a good source for this sort of thing. Other techblogs are available, you know.)