Contrary to the benchmark reports of Microsoft's April demo of the Windows Phone 7 "Mango" -- the then-Apple browser (pre-Nitro) didn't fared well against Android and Windows Mobile in a browser test that Microsoft set up. It had registered a 2 frames per second vs. Microsoft's Mobile IE score of 26. Apple was originally handicapped because the iPhone has more pixels to render: 640x960 vs. 480x800.
Now, amid the Nitro update and running the same test on a iOS 5 iPhone 4 with the latest Safari blows by the experimental IE9 in Mango and scores a 31 frames per second (fps). Check the screen shot below for the latest result and the video under the picture of April test.