It's a great 21" screen with the resolution of a 20" screen (1680*1050), which makes it all a bit larger. It has lots of extra connection possibilities, picture-in-picture capability,...
It is hi-res, so if you connect a tv settop box, a DVD player or a playstation 2, the image isn't that sharp (as their output resolution is too low).
Only neg is that it doesn't act as a USB hub.