I got the monitor as a second monitor for my iMac 21.5 and have to say that he is quite on a par with the Apple device. Admittedly, the display is a little worse, but that's to complain at a high level. On adequate brightness and contrast colors are very presentable. Even at the lowest brightness level to save power you get even offered an acceptable image.
Is highly recommended as a second monitor as well as the Dell Erstmonitor is a good choice!