on any mobile device DisplayMate has ever tested. Of course, the subject of the Pentile Display on the Samsung Galaxy S III came up and the testing showed that power limits inherent with OLED screens make the display on the Samsung Galaxy S III half as bright as the one on the Apple iPhone 5.
DisplayMate says that when it comes to the Color Gamut and Color Accuracy, Apple has made a strong effort in making colors very accurate on the iPhone. On the other hand, DisplayMate chides Samsung for not bothering to calibrate the Color Gamut on its OLED screens, leading to wildly inaccurate color representation includsing over saturation of colors which is a standard on AMOLED screens.
source: DisplayMate via BGR