Has anybody used a tv box to play a console on their PC?

I was considering buying one of those to hook up to my computer. My monitor is quite nice, so I thought it would be a cool idea, but I've never done this, nor do I know anybody in person who has done this.
I may have the term wrong for the device, but basically it is a box that allows you to watch television on your computer, but it also has the good ol' yellow white and red connectors.

So if you've ever tried this before how does it look? Better than the TV / Worse? Significant change at all?
Your response is much appreciated.